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Balbharti Maharashtra State Board 11th Biology Important Questions Chapter 7 Cell Division Important Questions and Answers.

Maharashtra State Board 11th Biology Important Questions Chapter 7 Cell Division

Question 1.
Why interphase is known as preparatory phase.
Answer:
1. During interphase, the cell is metabolically very active.
2. In this phase, a cell grows to its maximum size, chromosomal material (DNA and histone proteins) duplicates and the cell prepares itself for next mitotic division. Hence, inteiphase is known as preparatory phase.

Question 2.
Name the following.
1. In which phase the amount of DNA per cell doubles?
2. Which types of RNA are synthesized during first growth phase?
Answer:
1. S-phase.
2. m-RNA, t-RNA and r-RNA

Question 3.
Match the Column I (Phases of Cell cycle) with Column II (Approximate time for completion).

Answer:

Question 4.
What is cell division? Mention the types of cell division.
Answer:
The division of cells into two (or more) daughter cells with same (or different) genetic material is called cell division. There are three types of cell divisions:
1. Amitosis:
a. It is the simplest form of cell division. The nucleus elongates and a constriction appears along its length.
b. This constriction deepens and divides nucleus into two daughter nuclei followed by division of cytoplasm resulting in formation of two daughter cells.
c. This type of division is observed in unicellular organisms, abnormal cells, old cells and in foetal membrane cells.

2. Mitosis:
a. In this type of cell division, the cell divides and forms two similar daughter cells which are identical to the parent cell.
b. It is completed in two steps as karyokinesis and cytokinesis.

3. Meiosis:
a. In this type of cell division, the number of chromosomes is reduced to half. Hence, this type of cell division is also called reductional division.
b. Meiosis produces four haploid daughter cells from a diploid parent cell.

Question 5.
With the help of suitable diagrams, explain karyokinesis in brief.
Answer:
Karyokinesis is the nuclear division which is divided into prophase, metaphase, anaphase and telophase.
1. Prophase:
a. In this phase, condensation of chromatin material, migration of centrioles, appearance of mitotic apparatus and disappearance of nuclear membrane takes place.
b. Due to condensation, each chromosome with its sister chromatids connected by centromere is clearly visible under light microscope.
c. The nucleolus starts to disappear.
d. Centrosome start moving towards the opposite poles of the cell.
e. Mitotic apparatus is almost completely formed.

2. Metaphase:
a. Chromosomes are completely condensed and appear short.
b. Centromere and sister chromatids become very prominent.
c. All the chromosomes are arranged at equatorial plane of cell. This is called metaphase plate.
d. Mitotic spindle is fully formed in this phase.
e. Centromere of each chromosome divides horizontally into two, each being associated with a chromatid. [Note: The centromeres divide at the beginning of anaphase so that the two chromatids of each chromosome become separated from each other.
Source: Cell Division, Donald B. McMillan, Richard J. Harris, in An Atlas of Comparative Vertebrate Histology, 2018.]

3. Anaphase:
a. In this phase, chromatids of each chromosome separate and form two chromosomes called daughter chromosomes.
b. The chromosomes which are formed are pulled away in opposite direction by spindle apparatus.
c. Anaphase ends when each set of chromosomes reach at opposite poles of the cell.

4. Telophase:
a. This is the final stage of karyokinesis.
b. The chromosomes with their centromeres begin to uncoil at the poles.
c. The chromosomes lengthen and lose their individuality.
d. The nucleolus reappears and the nuclear membrane appear around the chromosomes.
e. Spindle fibres breakdown and get absorbed in the cytoplasm. Thus, two daughter nuclei are formed.

These are small disc-shaped structures at the surface of the centromeres which serve as the sites of attachment of spindle fibres to the chromosomes.

Question 6.
Draw neat and labelled diagram of Anaphase.
Answer:
Anaphase:
a. In this phase, chromatids of each chromosome separate and form two chromosomes called daughter chromosomes.
b. The chromosomes which are formed are pulled away in opposite direction by spindle apparatus.
c. Anaphase ends when each set of chromosomes reach at opposite poles of the cell.

Question 7.
Match the following.

Answer:

Question 8.
Observe the given diagram and explain the depicted process in your own words.

Answer:

1. The process depicted in the given diagram is cytokinesis in animal cell.
2. This step takes place at the end of karyokinesis (nuclear division) of mitosis.
3. It depicts the division of the cytoplasmic material in order to form two daughter cells that resemble each other.
4. The division starts with a constriction generally at the equator. This constriction gradually deepens and ultimately joins in the centre dividing into two cells.
5. At the time of cytoplasmic division, organelles like mitochondria and plastids get distributed between the two daughter cells.

Question 9.
Diagrammatically differentiate between cytokinesis in animal cell and plant cell.
Answer:

Question 10.
How cell wall is formed in plant cell?
Answer:
The formation of the new cell wall begins with the formation of a simple precursor, called the ‘cell-plate’ that represents the middle lamella between the walls of two adjacent cells.

Question 11.
What is necrosis?
Answer:
Necrosis is a form of cell injury which leads to the premature death of cells. For example: due to scrape or a harmful chemical.

Question 12.
What is apoptosis? Write its significance.
Answer:

1. Apoptosis also known as programmed cell death or cellular suicide. In apoptosis cells die in controlled way.
2. For example: during embryonic development the cells between the embryonic fingers die in a normal process called apoptosis to give a definite shape to the fingers.
3. Apoptosis also helps in eliminating potential cancer cells.

Question 13.
Which type of cell division is known as reductional division? Why?
Answer:
1. Meiosis is known as reductional division.
2. The number of chromosome is reduced to half, hence, meiosis is known as reductional division.

Question 14.
Describe the various phases of heterotypic division.
Answer:
Heterotypic division is first meiotic division, during which a diploid cell is divided into two haploid cells. The daughter cells resulting from this division are different from the parent cell in chromosome number. Hence the division is called heterotypic division.
It consists of following phases:
1. Prophase -I:
It is the most complicated and longest phase of meiotic division.
It is further divided into five sub-phases viz. leptotene, zygotene, pachytene, diplotene and diakinesis.

a. Leptotene:

1. The volume of the nucleus increases.
2. The chromosomes become long distinct and coiled.
3. They orient themselves in a specific fonn known as bouquet stage. This is characterized with the ends of chromosomes converged towards the side of nucleus where the centrosome lies.
4. The centriole duplicates into two and migrates to opposite poles. [Note: Centrioles divide during Gj phase of interphase.]

b. Zygotene:

1. Pairing of non-sister chromatids of homologous chromosomes takes place by formation of synaptonemal complex. This pairing is called synapsis.
2. Each pair consists of a maternal chromosome and a paternal chromosome. Chromosomal pairs are called bivalents or tetrads.

c. Pachytene:

1. Each individual chromosome begins to split longitudinally into two similar chromatids. Therefore, each bivalent now appears as a tetrad consisting of four chromatids.
2. The homologous chromosomes begin to separate but they do not separate completely and remain attached to one or more points. These points are called chiasmata (Appear like a cross-X).
3. Chromatids break at these points and broken segments are exchanged between non-sister chromatids of homologous chromosomes resulting in recombination.

d. Diplotene:
The chiasma becomes clearly visible in diplotene due to beginning of repulsion between synapsed homologous chromosomes. This is known as desynapsis. Synaptonemal complex also starts to disappear.

e. Diakinesis:

1. The chiasmata begin to move along the length of chromosomes from the centromere towards the ends of chromosomes. The displacement of chiasmata is termed as terminalization.
2. The terminal chiasmata exist till the metaphase.
3. The nucleolus and nuclear membrane completely disappear and spindle fibres begin to appear.

2. Metaphase -1:
a. The spindle fibres are well developed.
b. The tetrads orient themselves on equator in such a way that centromeres of homologous tetrads lie towards the poles and arms towards the equator.
c. They are ready to separate as repulsive force increases.
a. Homologous chromosomes are carried towards the opposite poles by spindle apparatus. This is known as disjunction.
b. The two sister chromatids of each chromosome do not separate in meiosis -I. This is reductional division.
c. The sister chromatids of each chromosome are connected by a common centromere.
d. Both sister chromatids of each chromosome are now different in genetic content as one of them has undergone recombination.

3. Anaphase – I:
1. Homologous chromosomes are carried towards the opposite poles by spindle apparatus. This is known as disjunction.
2. The two sister chromatids of each chromosome do not separate in meiosis -I. This is reductional division.
3. The sister chromatids of each chromosome are connected by a common centromere.
4. Both sister chromatids of each chromosome are now different in genetic content as one of them has undergone recombination.

4. Telophase-I:
a. The haploid number of chromosomes becomes uncoiled and elongated after reaching their respective poles.
b. The nuclear membrane and nucleolus reappear and thus two daughter nuclei are formed.

Cytokinesis -1:
Cytokinesis occurs after karyokinesis and two haploid cells are formed. In many cases, these daughter cells pass through interkinesis.

[Note: The association between the homologous chromosomes i.e. chiasmata remain till metaphase I. During metaphase /, the paired homologous chromosomes move to the metaphase plate. In anaphase [ the spindle fibers begin to shorten. As these spindle fibres shorten, the association between homologous chromosomes (chiasmata) are broken, allowing homologous chromosomes to be pulled to opposite poles.]

Question 15.
What is Homotypic Division? Explain its phases.
Answer:
Two haploid cells formed during first meiotic division divide further into four haploid cells this division is called homotypic division. It consists of five phases: prophase – II, metaphase – II, anaphase – II, telophase – II, and Cytokinesis – II.

1. Prophase-II:
a. The chromosomes are distinct with two chromatids.
b. Each centriole divides into two resulting in formation of two centrioles which migrate to opposite poles and form asters.
c. Spindle fibres are formed between the centrioles.
d. The nuclear membrane and nucleolus disappears in this phase.

2. Metaphase -II:
a. Chromosomes are arranged at the equator.
b. The two chromatids of each chromosome are separated by division of the centromere.
c. Some of the spindle fibres are attached to the centromeres and some are arranged end to end between two opposite centrioles.

3. Anaphase – II:
In this phase, the separated chromatids become daughter chromosomes and move to opposite poles due to the contraction of the spindle fibres attached to centromeres.

4. Telophase – II:
a. In this stage daughter chromosomes starts to uncoil.
b. The nuclear membrane surrounds each group of chromosomes.
c. Nucleolus reappears in this phase.

5. Cytokinesis – II
a. Cytokinesis takes place after the nuclear division.
b. Two haploid cells are formed from each haploid cell.
c. Thus, four haploid daughter cells are formed.
d. These cells then undergo changes to form gametes.

Question 16.
Why meiosis is important?
Answer:

1. Meiotic division produces gametes or spores.
2. If it is absent, the number of chromosomes would double or quadruple resulting in the formation of monstrosities (abnormal gametes).
3. The constant number of chromosomes in a given species across generations is maintained by meiosis and fertilization.
4. Because of crossing over, exchange of genetic material takes place leading to genetic variations, which are the raw materials for evolution.

Question 17.
Observe the diagram and answer the questions given below it.

1. Identify the type of cell division shown in the diagram.
2. Write its significance of meiosis.
Answer:
1. The type of cell division shown in diagram is meiosis II.
2. Meiotic division produces gametes or spores.

1. If it is absent, the number of chromosomes would double or quadruple resulting in the formation of monstrosities (abnormal gametes).
2. The constant number of chromosomes in a given species across generations is maintained by meiosis and fertilization.
3. Because of crossing over, exchange of genetic material takes place leading to genetic variations, which are the raw materials for evolution.

Question 18.
Explain Anaphase-I with a neat labelled diagram.
Answer:

Anaphase:
a. In this phase, chromatids of each chromosome separate and form two chromosomes called daughter chromosomes.
b. The chromosomes which are formed are pulled away in opposite direction by spindle apparatus.
c. Anaphase ends when each set of chromosomes reach at opposite poles of the cell.

Question 19.
What is crossing over? Give its significance.
Answer:
Crossing over:
The process of exchange of genetic material between non-sister chromatids of homologous chromosomes is known as crossing over.
Significance of crossing over:
Crossing over results in genetic recombination of parental characters that leads to variations.

Question 20.
What happens during diakinesis?
Answer:

1. In diakinesis, the chiasmata begin to move along the length of chromosomes from the centromere towards the ends of chromosomes.
2. The displacement of chiasmata is termed as terminalization. The terminal chiasmata exist till the metaphase.
3. The nucleolus disappears and the nuclear membrane also begins to disappear.
4. Spindle fibres starts to appear in the cytoplasm.

Question 21.
Differentiate between anaphase of mitosis and anaphase – I of meiosis.
Answer:

Question 22.
Give reasons: Meiosis is known as reductional division.
Answer:
Meiosis is known as reductional division because the parent cell produces four daughter cells each having half the number of chromosomes present in the parent cell.

Question 23.
Fill in the blanks:

1. The process of mitosis maintains the _______.
2. ________ involves the cell death, but it benefits the organism as a whole.
3. Crossing over takes place in _______ phase of Prophase-I.

Answer:

1. The process of mitosis maintains the nucleo-cytoplasmic ratio.
2. Apoptosis involves the cell death, but it benefits the organism as a whole.
3. Crossing over takes place in pachytene phase of Prophase-I.

Question 24.
1. Complete the following flowchart.
2. Explain the type of cell division in which chromosome number remain the same as that of the parent cell.

Answer:
Karyokinesis is the nuclear division which is divided into prophase, metaphase, anaphase and telophase.
1. Prophase:
a. In this phase, condensation of chromatin material, migration of centrioles, appearance of mitotic apparatus and disappearance of nuclear membrane takes place.
b. Due to condensation, each chromosome with its sister chromatids connected by centromere is clearly visible under light microscope.
c. The nucleolus starts to disappear.
d. Centrosome start moving towards the opposite poles of the cell.
e. Mitotic apparatus is almost completely formed.

2. Metaphase:
a. Chromosomes are completely condensed and appear short.
b. Centromere and sister chromatids become very prominent.
c. All the chromosomes are arranged at equatorial plane of cell. This is called metaphase plate.
d. Mitotic spindle is fully formed in this phase.
e. Centromere of each chromosome divides horizontally into two, each being associated with a chromatid. [Note: The centromeres divide at the beginning of anaphase so that the two chromatids of each chromosome become separated from each other.
Source: Cell Division, Donald B. McMillan, Richard J. Harris, in An Atlas of Comparative Vertebrate Histology, 2018.]

3. Anaphase:
a. In this phase, chromatids of each chromosome separate and form two chromosomes called daughter chromosomes.
b. The chromosomes which are formed are pulled away in opposite direction by spindle apparatus.
c. Anaphase ends when each set of chromosomes reach at opposite poles of the cell.

4. Telophase:
a. This is the final stage of karyokinesis.
b. The chromosomes with their centromeres begin to uncoil at the poles.
c. The chromosomes lengthen and lose their individuality.
d. The nucleolus reappears and the nuclear membrane appear around the chromosomes.
e. Spindle fibres breakdown and get absorbed in the cytoplasm. Thus, two daughter nuclei are formed.

These are small disc-shaped structures at the surface of the centromeres which serve as the sites of attachment of spindle fibres to the chromosomes.

Question 25.
While studying mitosis, different teams of students made following observations in the cells focused under microscope.
1. In certain cells chromosomes were arranged at equatorial plane with fibres originating from cylindrical structures at both the poles.
2. Few cells showed chromatids moving towards opposite poles.
a. In first observation which stage of mitosis is seen by students and what is the scientific term used to represent cylindrical structures?
b. Which stage is seen in the second observation?
Answer:
a. The stage observed in the first case is metaphase. The scientific term used to represent the cylindrical structures are centrioles.
b. The other stage seen in second observation is anaphase.

Question 26.
During biology practical students were asked to see the slide mounted under microscope and note down their observations. Few students noted that the stage observed is anaphase of mitosis and others said that it is anaphase I of meiosis. Later while explaining about experiments teacher said that it is anaphase I of meiosis. On what basis teacher confirmed that it is anaphase I of meiosis?
Answer:
Chromosomes moving towards opposite poles during anaphase I do not separate at the centromeres.

Question 27.
Colchicine is an alkaloid extracted from plants. It prevents the formation of spindle fibres. In the presence colchicine, if a cell enters mitosis what would be the outcome?
Answer:
The spindle fibres are necessary for segregating the sister chromatids to opposite poles of the cell during anaphase. In the presence of colchicine, no spindle fibres will form to attach to the kinetochores (small disc¬like structures present on chromosomes). Therefore, the cell will be stuck in mitosis with the condensed pairs of sister chromatids in an unorganized array.

Question 28.
Read the following statements and mention whether they are TRUE or FALSE in respective boxes.
1. Life of all multicellular organisms starts from single cell which is known as zygote.
2. Spindle fibres present between centriole and centromere are known as polar fibres which can contract.
3. Growth of every living organism depends on cell division.
4. Spindle fibres present between opposite centrioles are called as kinetochore fibres which can elongate.

Answer:
(C)

Question 29.
Quick Review

Question 30.
Exercise:

Question 1.
Define cell cycle.
Answer:

1. Sequential events occurring in the life of a cell is called cell cycle.
2. Interphase and M – phase are the two phases of cell cycle.
3. Cell undergoes growth or rest during interphase and divides during M – phase.

Question 2.
Observe the following diagram and the questions based on it.

1. If the initial amount of DNA in a cell is 2C then in which phase of cell cycle the amount of this DNA would become 4C? Also name the process.
2. Which sub-phase of the interphase is of short duration?
3. Enlist the phases of karyokinesis in proper order.
Answer:
S – phase (Synthesis phase):
In this phase DNA is synthesized (replicated), so that amount of DNA per cell doubles.
Synthesis of histone proteins takes place in this phase.
Karyokinesis is the nuclear division which is divided into prophase, metaphase, anaphase and telophase.
1. Prophase:
a. In this phase, condensation of chromatin material, migration of centrioles, appearance of mitotic apparatus and disappearance of nuclear membrane takes place.
b. Due to condensation, each chromosome with its sister chromatids connected by centromere is clearly visible under light microscope.
c. The nucleolus starts to disappear.
d. Centrosome start moving towards the opposite poles of the cell.
e. Mitotic apparatus is almost completely formed.

2. Metaphase:
a. Chromosomes are completely condensed and appear short.
b. Centromere and sister chromatids become very prominent.
c. All the chromosomes are arranged at equatorial plane of cell. This is called metaphase plate.
d. Mitotic spindle is fully formed in this phase.
e. Centromere of each chromosome divides horizontally into two, each being associated with a chromatid. [Note: The centromeres divide at the beginning of anaphase so that the two chromatids of each chromosome become separated from each other.
Source: Cell Division, Donald B. McMillan, Richard J. Harris, in An Atlas of Comparative Vertebrate Histology, 2018.]

3. Anaphase:
a. In this phase, chromatids of each chromosome separate and form two chromosomes called daughter chromosomes.
b. The chromosomes which are formed are pulled away in opposite direction by spindle apparatus.
c. Anaphase ends when each set of chromosomes reach at opposite poles of the cell.

4. Telophase:
a. This is the final stage of karyokinesis.
b. The chromosomes with their centromeres begin to uncoil at the poles.
c. The chromosomes lengthen and lose their individuality.
d. The nucleolus reappears and the nuclear membrane appear around the chromosomes.
e. Spindle fibres breakdown and get absorbed in the cytoplasm. Thus, two daughter nuclei are formed.

These are small disc-shaped structures at the surface of the centromeres which serve as the sites of attachment of spindle fibres to the chromosomes.

Question 3.
During which stage of Prophase-I synapsis occurs?
Answer:
b. Zygotene:
Pairing of non-sister chromatids of homologous chromosomes takes place by formation of synaptonemal complex. This pairing is called synapsis.
Each pair consists of a maternal chromosome and a paternal chromosome. Chromosomal pairs are called bivalents or tetrads.

Question 4.
During which stage disjunction takes place?
Answer:
Telophase-I:
a. The haploid number of chromosomes becomes uncoiled and elongated after reaching their respective poles.
b. The nuclear membrane and nucleolus reappear and thus two daughter nuclei are formed.

Question 5.
What is disjunction?
Answer:
Telophase-I:
a. The haploid number of chromosomes becomes uncoiled and elongated after reaching their respective poles.
b. The nuclear membrane and nucleolus reappear and thus two daughter nuclei are formed.

Question 6.
Why meiosis is known as reductional division?
Answer:
In this type of cell division, the number of chromosomes is reduced to half. Hence, this type of cell division is also called reductional division.

Question 7.
Sketch and label the phase of cell division in which synaptonemal complex is formed?
Answer:
Zygotene:
Pairing of non-sister chromatids of homologous chromosomes takes place by formation of synaptonemal complex. This pairing is called synapsis.
Each pair consists of a maternal chromosome and a paternal chromosome. Chromosomal pairs are called bivalents or tetrads.

Question 8.
Make a schematic representation of a type of cell division in which chromosome number is reduced to half.
Answer:
Karyokinesis is the nuclear division which is divided into prophase, metaphase, anaphase and telophase.
1. Prophase:
a. In this phase, condensation of chromatin material, migration of centrioles, appearance of mitotic apparatus and disappearance of nuclear membrane takes place.
b. Due to condensation, each chromosome with its sister chromatids connected by centromere is clearly visible under light microscope.
c. The nucleolus starts to disappear.
d. Centrosome start moving towards the opposite poles of the cell.
e. Mitotic apparatus is almost completely formed.

2. Metaphase:
a. Chromosomes are completely condensed and appear short.
b. Centromere and sister chromatids become very prominent.
c. All the chromosomes are arranged at equatorial plane of cell. This is called metaphase plate.
d. Mitotic spindle is fully formed in this phase.
e. Centromere of each chromosome divides horizontally into two, each being associated with a chromatid. [Note: The centromeres divide at the beginning of anaphase so that the two chromatids of each chromosome become separated from each other.
Source: Cell Division, Donald B. McMillan, Richard J. Harris, in An Atlas of Comparative Vertebrate Histology, 2018.]

3. Anaphase:
a. In this phase, chromatids of each chromosome separate and form two chromosomes called daughter chromosomes.
b. The chromosomes which are formed are pulled away in opposite direction by spindle apparatus.
c. Anaphase ends when each set of chromosomes reach at opposite poles of the cell.

4. Telophase:
a. This is the final stage of karyokinesis.
b. The chromosomes with their centromeres begin to uncoil at the poles.
c. The chromosomes lengthen and lose their individuality.
d. The nucleolus reappears and the nuclear membrane appear around the chromosomes.
e. Spindle fibres breakdown and get absorbed in the cytoplasm. Thus, two daughter nuclei are formed.

These are small disc-shaped structures at the surface of the centromeres which serve as the sites of attachment of spindle fibres to the chromosomes.

Question 9.
Describe mitosis and its stages in brief.
Answer:
Karyokinesis is the nuclear division which is divided into prophase, metaphase, anaphase and telophase.
1. Prophase:
a. In this phase, condensation of chromatin material, migration of centrioles, appearance of mitotic apparatus and disappearance of nuclear membrane takes place.
b. Due to condensation, each chromosome with its sister chromatids connected by centromere is clearly visible under light microscope.
c. The nucleolus starts to disappear.
d. Centrosome start moving towards the opposite poles of the cell.
e. Mitotic apparatus is almost completely formed.

2. Metaphase:
a. Chromosomes are completely condensed and appear short.
b. Centromere and sister chromatids become very prominent.
c. All the chromosomes are arranged at equatorial plane of cell. This is called metaphase plate.
d. Mitotic spindle is fully formed in this phase.
e. Centromere of each chromosome divides horizontally into two, each being associated with a chromatid. [Note: The centromeres divide at the beginning of anaphase so that the two chromatids of each chromosome become separated from each other.
Source: Cell Division, Donald B. McMillan, Richard J. Harris, in An Atlas of Comparative Vertebrate Histology, 2018.]

3. Anaphase:
a. In this phase, chromatids of each chromosome separate and form two chromosomes called daughter chromosomes.
b. The chromosomes which are formed are pulled away in opposite direction by spindle apparatus.
c. Anaphase ends when each set of chromosomes reach at opposite poles of the cell.

4. Telophase:
a. This is the final stage of karyokinesis.
b. The chromosomes with their centromeres begin to uncoil at the poles.
c. The chromosomes lengthen and lose their individuality.
d. The nucleolus reappears and the nuclear membrane appear around the chromosomes.
e. Spindle fibres breakdown and get absorbed in the cytoplasm. Thus, two daughter nuclei are formed.

These are small disc-shaped structures at the surface of the centromeres which serve as the sites of attachment of spindle fibres to the chromosomes.

Question 10.
Describe chiasmata. Draw diagram to illustrate your answer.
Answer:
Pachytene:
Each individual chromosome begins to split longitudinally into two similar chromatids. Therefore, each bivalent now appears as a tetrad consisting of four chromatids.
The homologous chromosomes begin to separate but they do not separate completely and remain attached to one or more points. These points are called chiasmata (Appear like a cross-X).
Chromatids break at these points and broken segments are exchanged between non-sister chromatids of homologous chromosomes resulting in recombination.

Diplotene:
The chiasma becomes clearly visible in diplotene due to beginning of repulsion between synapsed homologous chromosomes. This is known as desynapsis. Synaptonemal complex also starts to disappear.

Question 11.
Correct the following diagram and write a short note on it.

Answer:
b. Zygotene:
Pairing of non-sister chromatids of homologous chromosomes takes place by formation of synaptonemal complex. This pairing is called synapsis.
Each pair consists of a maternal chromosome and a paternal chromosome. Chromosomal pairs are called bivalents or tetrads.

Question 12.
Explain prophase I in your own words.
Answer:
Prophase -I:
It is the most complicated and longest phase of meiotic division.
It is further divided into five sub-phases viz. leptotene, zygotene, pachytene, diplotene and diakinesis.

Question 13.
Explain homotypic division.
Answer:
Two haploid cells formed during first meiotic division divide further into four haploid cells this division is called homotypic division. It consists of five phases: prophase – II, metaphase – II, anaphase – II, telophase – II, and Cytokinesis – II.

1. Prophase-II:
a. The chromosomes are distinct with two chromatids.
b. Each centriole divides into two resulting in formation of two centrioles which migrate to opposite poles and form asters.
c. Spindle fibres are formed between the centrioles.
d. The nuclear membrane and nucleolus disappears in this phase.

2. Metaphase -II:
a. Chromosomes are arranged at the equator.
b. The two chromatids of each chromosome are separated by division of the centromere.
c. Some of the spindle fibres are attached to the centromeres and some are arranged end to end between two opposite centrioles.

3. Anaphase – II:
In this phase, the separated chromatids become daughter chromosomes and move to opposite poles due to the contraction of the spindle fibres attached to centromeres.

4. Telophase – II:
a. In this stage daughter chromosomes starts to uncoil.
b. The nuclear membrane surrounds each group of chromosomes.
c. Nucleolus reappears in this phase.

5. Cytokinesis – II
a. Cytokinesis takes place after the nuclear division.
b. Two haploid cells are formed from each haploid cell.
c. Thus, four haploid daughter cells are formed.
d. These cells then undergo changes to form gametes.

Question 14.
How does cytokinesis in plant cells differ from animal cells?
Answer:
The formation of the new cell wall begins with the formation of a simple precursor, called the ‘cell-plate’ that represents the middle lamella between the walls of two adjacent cells.

Question 15.
What is the significance of meiosis in sexually reproducing animals?
Answer:

1. Meiotic division produces gametes or spores.
2. If it is absent, the number of chromosomes would double or quadruple resulting in the formation of monstrosities (abnormal gametes).
3. The constant number of chromosomes in a given species across generations is maintained by meiosis and fertilization.
4. Because of crossing over, exchange of genetic material takes place leading to genetic variations, which are the raw materials for evolution.
5. Gametes are produced by the process of meiosis which are essential for sexual reproduction.
6. Diploid organisms have two set of chromosomes (one paternal and one maternal).
7. For a diploid organism to undergo sexual reproduction it needs to create gametes that contain only one set of chromosomes so the number of chromosomes remains same in the next generation.
8. In absence of meiosis, the chromosome number of parents and their offsprings will differ in every generation; hence no species will hold its characters.
9. Also, there will be no crossing over of homologous chromosomes. Thus, there will be no variations with respect to the changing environment in progeny to maintain their existence, which may lead to extinction of species.

Question 16.
Explain the first three stages of Meiosis II.
Answer:
Two haploid cells formed during first meiotic division divide further into four haploid cells this division is called homotypic division. It consists of five phases: prophase – II, metaphase – II, anaphase – II, telophase – II, and Cytokinesis – II.

1. Prophase-II:
a. The chromosomes are distinct with two chromatids.
b. Each centriole divides into two resulting in formation of two centrioles which migrate to opposite poles and form asters.
c. Spindle fibres are formed between the centrioles.
d. The nuclear membrane and nucleolus disappears in this phase.

2. Metaphase -II:
a. Chromosomes are arranged at the equator.
b. The two chromatids of each chromosome are separated by division of the centromere.
c. Some of the spindle fibres are attached to the centromeres and some are arranged end to end between two opposite centrioles.

3. Anaphase – II:
In this phase, the separated chromatids become daughter chromosomes and move to opposite poles due to the contraction of the spindle fibres attached to centromeres.

4. Telophase – II:
a. In this stage daughter chromosomes starts to uncoil.
b. The nuclear membrane surrounds each group of chromosomes.
c. Nucleolus reappears in this phase.

5. Cytokinesis – II
a. Cytokinesis takes place after the nuclear division.
b. Two haploid cells are formed from each haploid cell.
c. Thus, four haploid daughter cells are formed.
d. These cells then undergo changes to form gametes.

Question 17.
Sketch, label and describe telophase in mitosis.
Answer:
Telophase:
a. This is the final stage of karyokinesis.
b. The chromosomes with their centromeres begin to uncoil at the poles.
c. The chromosomes lengthen and lose their individuality.
d. The nucleolus reappears and the nuclear membrane appear around the chromosomes.
e. Spindle fibres breakdown and get absorbed in the cytoplasm. Thus, two daughter nuclei are formed.

These are small disc-shaped structures at the surface of the centromeres which serve as the sites of attachment of spindle fibres to the chromosomes.

Question 18.
Explain the process recombination.
Answer:
a. Recombination is exchange of genetic material between paternal and maternal chromosomes during gamete formation.
b. The points where crossing over takes place is known as chiasmata.
c. Chromatids acquire new combinations of alleles by physically exchanging segments in crossing-over.
d. The exchange of genetic material between homologous chromosomes involves accurate breakage and joining of DNA molecules through a complex mechanism.
e. It is catalyzed by enzymes.

Question 19.
1. What is necrosis?
2. What is apoptosis? Mention its significance.
Answer:
1. Necrosis is a form of cell injury which leads to the premature death of cells. For example: due to scrape or a harmful chemical.
(2) 1. Apoptosis also known as programmed cell death or cellular suicide. In apoptosis cells die in controlled way.
2. For example: during embryonic development the cells between the embryonic fingers die in a normal process called apoptosis to give a definite shape to the fingers.
3. Apoptosis also helps in eliminating potential cancer cells.

Question 20.
Multiple Choice Questions:

Question 1.
Replication of DNA takes place during
(A) prophase
(B) S-phase
(C) G₂ phase
(D) Interkinesis
Answer:
(B) S-phase

Question 2.
During cell division, spindle fibers are attached to
(A) telomere
(B) centromere
(C) chromomeres
(D) chromosome
Answer:
(B) centromere

Question 3.
Which of the following is the shortest phase?
(A) metaphase
(B) anaphase
(C) interphase
(D) S-phase
Answer:
(B) anaphase

Question 4.
Reappearance of nucleolus is during
(A) telophase
(B) prophase
(C) cytokinesis
(D) inter-kinesis
Answer:
(A) telophase

Question 5.
During telophase,
(A) nuclear membrane is formed.
(B) nucleolus appears.
(C) astral rays disappear.
(D) all the above
Answer:
(D) all the above

Question 6.
Cytokinesis in plant cell takes place by
(A) furrowing
(B) cell plate formation
(C) any one of (A) or (B)
(D) none of these
Answer:
(B) cell plate formation

Question 7.
Meiosis is a
(A) homotypic division
(B) equatorial division
(C) reductional division
(D) none of the above
Answer:
(C) reductional division

Question 8.
Formation of Synaptonemal complex during meiosis occurs at
(A) Leptotene
(B) Zygotene
(C) Diplotene
(D) Pachytene
Answer:
(B) Zygotene

Question 9.
Crossing over takes place in the ________ stage.
(A) leptotene
(B) zygotene
(C) pachytene
(D) diplotene
Answer:
(C) pachytene

Question 10.
Crossing over takes place between
(A) sister chromatids
(B) non-homologous chromosomes
(C) non-sister chromatids of homologues
(D) any two chromatids
Answer:
(C) non-sister chromatids of homologues

Question 11.
Crossing over of chromosomes during meiosis leads to
(A) mutation
(B) sex determination
(C) new gene combination
(D) loss of chromosomes
Answer:
(C) new gene combination

Question 12.
Points at which crossing over has taken place between homologous chromosomes are called
(A) chiasmata
(B) synaptonemal complexes
(C) centromeres
(D) telomere
Answer:
(A) chiasmata

Question 13.
Which of the following events take place during diplotene stage of prophase I of meiosis?
(A) Compaction of chromosomes
(B) Formation of synapsis
(C) Process of crossing over
(D) Repulsion of homologues
Answer:
(D) Repulsion of homologues

Question 14.
The correct sequence of stages in prophase I of meiosis is
(A) Leptotene, Pachytene, Zygotene, Diakinesis, Diplotene
(B) Zygotene, Leptotene, Pachytene, Diakinesis, Diplotene
(C) Leptotene, Zygotene, Pachytene, Diplotene, Diakinesis
(D) Diplotene, Diakinesis, Pachytene, Zygotene, Leptotene
Answer:
(C) Leptotene, Zygotene, Pachytene, Diplotene, Diakinesis

Question 15.
In which phase of meiosis are homologous chromosomes separated?
(A) Anaphase I
(B) Prophase II
(C) Anaphase II
(D) Prophase I
Answer:
(A) Anaphase I

Question 16.
Mitosis differs from meiosis in not having
(A) Long prophase
(B) duplication of DNA
(C) Synapsis and crossing over
(D) interphase
Answer:
(C) Synapsis and crossing over

Question 17.
How many divisions are required to produce 128 gametes?
(A) 64
(B) 16
(C) 32
(D) 12
Answer:
(C) 32

Question 18.
Number of cells undergoing meiotic divisions to produce 124 microspores in angiosperm is
(A) 62
(B) 31
(C) 124
(D) 8
Answer:
(B) 31

Question 19.
How many haploid daughter cells are produced at the end of meiosis-II?
(A) 2
(B) 4
(C) 6
(D) 8
Answer:
(B) 4

Question 21.
Competitive Corner:

Question 1.
Crossing over takes place between which chromatids and in which stage of the cell cycle?
(A) Non-sister chromatids of nonhomologous chromosomes at Pachytene stage of prophase I
(B) Non-sister chromatids of nonhomologous chromosomes at Zygotene stage of prophase I
(C) Non-sister chromatids of homologous chromosomes at Pachytene stage of prophase I
(D) Non-sister chromatids of homologous chromosomes at Zygotene stage of prophase I
Answer:
(C) Non-sister chromatids of homologous chromosomes at Pachytene stage of prophase I

Question 2.
After meiosis I, the resultant daughter cells have
(A) four times the amount of DNA in comparison to haploid gamete.
(B) same amount of DNA as in the parent cell in S phase.
(C) twice the amount of DNA in comparison to haploid gamete.
(D) same amount of DNA in comparison to haploid gamete.
Answer:
(C) twice the amount of DNA in comparison to haploid gamete.

Question 3.
Cells in G₀ phase
(A) suspend the cell cycle
(B) terminate the cell cycle
(C) exit the cell cycle
(D) enter the cell cycle
Answer:
(C) exit the cell cycle

Question 4.
The CORRECT sequence of phases of cell cycle is: [NEET (UG) 2019]
(A) S → G₁ → G₂ → M
(B) G₁ → S → G₂ → M
(C) M → G₁ → G₂ → S
(D) G₁ → G₂ → S → M
Answer:
(B) G₁ → S → G₂ → M

Question 5.
The stage during which separation of the paired homologous chromosomes begins is
(A) Diakinesis
(B) Diplotene
(C) Pachytene
(D) Zygotene
Answer:
(B) Diplotene

Question 6.
Which of the following options gives the correct sequence of events during mitosis?
(A) Condensation → nuclear membrane disassembly → crossing over – segregation → telophase
(B) Condensation → nuclear membrane disassembly → arrangement at equator → centromere division → segregation → telophase
(C) Condensation → crossing over → nuclear membrane disassembly → segregation → telophase
(D) Condensation → arrangement at equator → centromere division → segregation → telophase
Answer:
(B) Condensation → nuclear membrane disassembly → arrangement at equator → centromere division → segregation → telophase

Question 7.
Which of the following is not a characteristic feature during mitosis in somatic cells?
(A) Chromosome movement
(B) Synapsis
(C) Spindle fibres
(D) Disappearance of nucleolus
Answer:
(B) Synapsis

Question 8.
Arrange the following events of meiosis in correct sequence. [AIPMT Retest 2015]
(a) Crossing over
(b) Synapsis
(c) Terminalisation of chiasmata
(d) Disappearance of nucleolus
(A) (b), (c), (d), (a)
(B) (b), (a), (d), (c)
(C) (b),(a), (c), (d)
(D) (a), (b), (c), (d)
Answer:
(C) (b),(a), (c), (d)

Balbharti Maharashtra State Board 11th Commerce Book Keeping & Accountancy Important Questions Chapter 4 Ledger Important Questions and Answers.

Maharashtra State Board 11th Commerce BK Important Questions Chapter 4 Ledger

1. Answer in one sentence only.

Question 1.
State the meaning of ‘Debit Balance’.
Answer:
Excess of the debit total of an account over its credit total is called debit balance.

Question 2.
What do you mean by Credit Balance?
Answer:
Excess of credit total of an account over its debit total is called credit balance.

Question 3.
What is the balance of Outstanding Salary A/c?
Answer:
The balance of Outstanding Salary A/c is a credit balance.

Question 4.
What is the balance of Cash A/c?
Answer:
The balance of Cash A/c is always a debit balance.

Question 5.
Where is the balance of Salaries A/c transferred at the end of the year?
Answer:
At the end of the year, the balance of Salaries A/c is transferred to Profit and Loss A/c.

Question 6.
From which books of accounts posting is made in the Ledger?
Answer:
From Journal and Subsidiary books posting is made in the ledger.

Question 7.
What do you mean by the head of an Account?
Answer:
The name of the account which is written on the top of the ledger account in the middle is called “Head of an account”.

2. Write the word, term, phrase, which can substitute each of the statements.

Question 1.
A bound book of Account.
Answer:
Ledger

Question 2.
The credit balance of the Bank Account.
Answer:
Bank Overdraft

Question 3.
Recording of transactions from Journal to Ledger.
Answer:
Ledger Posting

Question 4.
Page number of Ledger.
Answer:
L.F. No.

Question 5.
The right-hand side of an account.
Answer:
Credit Side

Question 6.
The left-hand side of an account.
Answer:
Debit Side

Question 7.
Excess of a debit total of an account over its credit total.
Answer:
Debit Balance

Question 8.
Excess of credit total of an account over its debit total.
Answer:
Credit Balance

Question 9.
A secondary book of account in which entries are recorded from Journal or Subsidiary books.
Answer:
Ledger

Question 10.
Page of the account book.
Answer:
Folio

Question 11.
A book of accounts in which all ledger accounts are maintained.
Answer:
Ledger

Question 12.
Type of accounts that are not balanced but transferred to Trading Account or P/L A/c.
Answer:
Nominal Accounts

Question 13.
An account where the total purchase book is posted.
Answer:
Purchases Account

Question 14.
A statement of accounts’s prepared from the balances of the ledger account.
Answer:
Trial Balance

3. Select appropriate alternatives from those given below and rewrite the sentences.

Question 1.
_______________ is the act of transferring an entry from journal to ledger.
(a) Journalising
(b) Casting
(c) Balancing
(d) Posting
Answer:
(d) Posting

Question 2.
Cash account always shows _______________ balance.
(a) Credit
(b) Negative
(c) Minus
(d) Debit
Answer:
(d) Debit

Question 3.
Bank overdraft means _______________ balance of Bank A/c.
(a) Debit
(b) Credit
(c) Positive
(d) Nil
Answer:
(b) Credit

Question 4.
Real accounts generally shows _______________ balance.
(a) Debit
(b) Credit
(c) Negative
(d) Nil
Answer:
(a) Debit

Question 5.
Excess of debit total of an account over it’s credit total indicates _______________ balance.
(a) Negative
(b) Positive
(c) Debit
(d) Credit
Answer:
(c) Debit

Question 6.
When goods are sold on credit _______________ account is credited.
(a) Buyer’s A/c
(b) Cash A/c
(c) Sales A/c
(d) Seller’s A/c
Answer:
(c) Sales A/c

Question 7.
When the total of debit side of an account exceeds credit side, it is called _______________ balance.
(a) Debit
(b) Credit
(c) Nil
(d) Real
Answer:
(a) Debit

Question 8.
Machinery A/c shows _______________ balance.
(a) Credit
(b) Debit
(c) Positive
(d) Negative
Answer:
(b) Debit

Question 9.
Left hand side of an account is called _______________
(a) Credit
(b) Debit
(c) Middle
(d) Centre
Answer:
(b) Debit

Question 10.
_______________ is prepared from the balances in the ledger accounts.
(a) List
(b) Journal
(c) Book
(d) Trial Balance
Answer:
(d) Trial Balance

Question 11.
Total of Sales book is _______________ to sales account.
(a) entered
(b) moved
(c) posted
(d) given
Answer:
(c) posted

Question 12.
Wages A/c is transferred to _______________ A/c.
(a) Trading A/c
(b) Profit & Loss A/c
(c) Trial Balance
(d) Any
Answer:
(a) Trading A/c

Question 13.
All entries are posted from Journal to _______________
(a) Ledger
(b) Balance Sheet
(c) Trial Balance
(d) Cash A/c
Answer:
(a) Ledger

4. State whether the following statements are ‘True or False’ with reasons.

Question 1.
Ledger accounts are balanced every day.
Answer:
This statement is False.
Ledger accounts are balanced on a particular period of time or on the accounting year of the firm. They are not balanced every day.

Question 2.
Every account is divided into two sides.
Answer:
This statement is True.
Every account is divided into two sides i.e. Debit and Credit to do ledger pasting from a journal which follows the rules of double-entry book-keeping.

Question 3.
The discount allowed is a real account.
Answer:
This statement is False.
Discount allowed is an expense for the business. All expenses come under the Nominal account. So the discount allowed is a Nominal account.

Question 4.
The bank is a Nominal A/c.
Answer:
This statement is False.
A bank is an Artificial person created by law. The bank is personal accounts.

Question 5.
Accounts of expenses may show a credit balance.
Answer:
This statement is False.
Accounts of expenses always show debit balance. They fall under the nominal account and its Golden rule is to Debit all Expenses.

Question 6.
A Debtors A/c always show a credit balance.
Answer:
This statement is False.
A Debtor A/c always shows a Debit balance. The debtor is a personal account and as per the rule of personal account Debit the receiver.

Question 7.
When goods are sold for cash, the personal a/c of the buyer is debited.
Answer:
This statement is False.
In a cash transaction, there is no Personal A/c. The personal account comes in a credit transaction. So when goods are sold for cash, the cash account is debited. A cash account is a real account and as per rule debit what comes in.

Question 8.
Capital a/c is a nominal a/c.
Answer:
This statement is False.
Capital is a Personal account. Capital is the amount invested by the proprietor in his business. A proprietor is a person. Capital is also personal A/c.

Question 9.
Drawing a/c is a personal a/c.
Answer:
This statement is True.
Drawings mean cash or goods withdrawn by the proprietor for his personal or family use he is a person. So drawing is personal A/c.

Question 10.
Narration is not necessary for a ledger.
Answer:
This statement is False.
Narration is necessary for a Journal book and not in Ledger. Ledgers are self-narrative as every ledger has headed.

Question 11.
All a/c’s are closed down at the end of the accounting year.
Answer:
This statement is True.
All ledger accounts are closed an accounting year or Financial year to prepare the Trial balance and Financial statements of the year.

Question 12.
Recording of a transaction in the journal is called posting.
Answer:
This statement is False.
The process of recording a transaction in the Journal is called Journalising. Posting means transferring journal entries to respective ledger accounts.

Question 13.
Balance of personal a/c is brought down for the next year.
Answer:
This statement is True.
Personal accounts are the account of Debtors or Creditors. The business has to collect or pay amounts on personal accounts. Current year collections or payments are done in the following year. So balances of personal accounts are brought for the next year.

Question 14.
All transactions are recorded directly in the ledger.
Answer:
This statement is False.
First, every transaction is recorded in a Journal book or Subsidiary book and from there they are posted to respective ledger accounts. No transaction can be recorded directly in the ledger.

Question 15.
Ledger Folio and index are necessary for the ledger.
Answer:
This statement is True.
The index is necessary to final particular account on its page number and ledger folio number is also necessary for cross-checking with the journal book. This makes handling convenient and easier.

Question 16.
Ledger posting is not necessary for journal proper.
Answer:
This statement is False.
Ledger posting is necessary for journal proper. From Ledger trial balance and financial statements are prepared for the accounting year. Without posting of journal proper Trial balance and financial statements will not be tally and can’t give true and fair accounting.

Question 17.
Ledger Folio is recorded in the journal.
Answer:
This statement is True.
Ledger folio is a page of the ledger, where posting is made from a journal book. For cross-reference, the ledger folio is recorded in the journal.

Question 18.
Ledger posting is made before journal entry.
Answer:
This statement is False.
Ledger posting is made after journal entry. First, all transactions are recorded to Journal and from the journal, posting is made to Ledger.

5. Fill in the blanks.

Question 1.
Debtors A/c shows _______________ balance.
Answer:
Debit

Question 2.
Left hand side of an account is called _______________ side.
Answer:
Debit

Question 3.
_______________ is prepared from the balances in the Ledger A/c.
Answer:
Trial Balance

Question 4.
Total of salary A/c is transfered to _______________ A/c.
Answer:
Profit and loss A/c

Question 5.
b/d (brought down) balance indicates _______________ balance.
Answer:
Opening

Question 6.
_______________ Balance on Nominal Account shows Inconies or gains.
Answer:
Credit

Question 7.
Debtors A/c shows _______________ balance.
Answer:
Debit

Question 8.
Drawing A/c shows _______________ balance.
Answer:
Debit

Question 9.
Wages A/c balance transferred to _______________ A/c.
Answer:
Profit and Loss

Question 10.
Discount allowed shows _______________ Balance.
Answer:
Debit

Question 11.
Dividend received shows _______________ Balance.
Answer:
Credit

Question 12.
Ledger is the _______________ book of Accounts.
Answer:
Principal

6. Complete the following table.

Question 1.

Answer:
Credit balance

Question 2.

Answer:
Ledger

Question 3.

Answer:
Credit Balance

Question 4.

Answer:
Livestock A/c

Question 5.

Answer:
Output GST

7. Put ‘✓’ mark for the nature of balance for the following.

Question 1.

Answer:

Balbharti Maharashtra State Board 11th Biology Important Questions Chapter 6 Biomolecules Important Questions and Answers.

Maharashtra State Board 11th Biology Important Questions Chapter 6 Biomolecules

Question 1.
How are living organisms classified? Give examples of each.
Answer:
1. Living organisms are classified as unicellular (consisting of single cell) and multicellular (having many cells).
2. Example of unicellular organisms: bacteria, yeast.
Example of multicellular organisms: plants, animals.

Question 2.
What is biochemistry?
Answer:
1. Biochemistry is biological chemistry that provides us the idea of the chemistry of living organisms and molecular basis for changes taking place in plants, animals and microbial cells.
2. It develops the foundation for understanding all biological processes and communication within and between cells as well as chemical basis of inheritance and diseases in animals and plants.

Question 3.
What does chemical analysis of living organisms indicate?
Answer:
Chemical analysis of all living organisms indicates the presence of the most common elements like carbon, hydrogen, nitrogen, oxygen, sulphur, calcium, phosphorus, magnesium and others with their respective content per unit mass of a living tissue.

Question 4.
Name the basic macromolecules present in the living organisms.
Answer:
Polysaccharides (carbohydrate) polymer of monosaccharide, polypeptides (proteins) polymer of amino acids and polynucleotides (nucleic acids) polymer of nucleotides are the three basic macromolecule present in the living organisms.

Question 5.
Draw a flowchart showing classification of carbohydrates.
Answer:

Question 6.
Write a short note on
1. Glucose
2. Galactose and
3. Fructose.
Answer:
1. Glucose:
a. It is the most important fuel in living cells.
b. Its concentration in the human blood is about 90mg per 100ml of blood.
c. The small size and solubility in water of glucose molecules allows them to pass through the cell membrane into the cell.
d. Energy is released when the molecules are metabolized by cellular respiration.

2. Galactose:
a. It looks very similar to glucose molecules.
b. They can also exist in a and p forms.
c. Galactose react with glucose to form the disaccharide lactose.
d. However, glucose and galactose cannot be easily converted into one another.
e. Galactose cannot play the same role in respiration as glucose.

3. Fructose:
a. It is the fruit sugar and chemically it is ketohexose but it has a five-atom ring rather than a six-atom ring.
b. Fructose reacts with glucose to form the sucrose, a disaccharide.

Question 7.
How are disaccharides absorbed through the cell membrane?
Answer:
1. Disaccharides are soluble in water but they are too big to pass through the cell membrane by diffusion.
2. They are broken down in the small intestine during digestion.
3. Thus, formed monosaccharides then pas into the blood and through cell membranes into the cells.

Question 8.
Identify the X and Y in the following structure of a disaccharide.
Answer:

X: Glycosidic bond Y: Glucose

Question 9.
Distinguish between monosaccharides and disaccharides.
Answer:

Question 10.
Which macromolecules are too big to escape from the cell?
Answer:
Polysaccharides are too big to escape from the cell.

Question 11.
Write a short note on
1. Starch
2. Glycogen
3. Cellulose.
Answer:
1. Starch:
a. Starch is a stored food in the plants.
b. Starch contains two types of glucose polymer: amylose and amylopectin.
c. Both are made from a-glucose.
d. Amylose is an unbranched polymer of a-glucose.
e. The molecules coil into a helical structure.
f. It foims a colloidal suspension in hot water.
g. Amylopectin is a branched polymer of a-glucose.
h. It is completely insoluble in water.

2. Glycogen:
a. It is amylopectin with very short distances between the branching side-chains.
b. Glycogen is stored in animal body particularly in liver and muscles from where it is hydrolyzed as per need to produce glucose.

3. Cellulose:
a. It is a polymer made from P-glucosc molecules and the polymer molecules are ‘straight’.
b. Cellulose serves to form the cell walls in plant cells.
c. These are much tougher than cell membranes.
d. This toughness is due to the arrangement of glucose units in the polymer chain and the hydrogen-bonding between neighbouring chains.

Question 12.
Why plant fats are liquid at room temperature while animal fats are solid?
Answer:

1. Plant fats are unsaturated fatty acids, whereas animal fats are saturated fatty acids.
2. Fats having unsaturated fatty acids are liquid at room temperature.
3. Saturated fatty acids are solid at room temperature. Hence, plant fats are liquid at room temperature, while animal fats are solid.

Question 13.
Draw the structure of triglyceride.
Answer:

Question 14.
Observe the following diagram and answer the questions based on it.
1. Identify the part ‘X’ in the given diagram.
2. What is the chemical property of the part ‘X’.
Answer:
1. The part labelled as ‘X’ is non-polar tail.
2. Non-polar tails are hydrophobic in nature.

Question 15.
Give two examples of unsaturated fatty acids.
Answer:
Oleic acid and linoleic acid are the examples of unsaturated fatty acids.

Question 16.
Explain primary structure of protein.
Answer:
The linear sequence of amino acids in polypeptide chain of a protein forms the primary structure of a protein.

Question 17.
Explain the secondary structure of protein with examples.
Answer:

1. There are two types of secondary structure of protein: a-helix and P-pleated sheets.
2. The polypeptide chain is arranged in a spiral helix. These spiral helices are of two types: a-helix (right handed) and P-helix (left handed).
3. This spiral configuration is held together by hydrogen bonds.
4. The sequence of amino acids in the polypeptide chain determines the location of its bend or fold and the position of formation of hydrogen bonds between different portions of the chain or between different chains. Thus, peptide chains form an a-helix structure.
5. Example of a-helix structure is keratin.
6. In some proteins two or more peptide chains are linked together by intermolecular hydrogen bonds. Such structures are called P-pleated sheets.
7. Example of P-pleated sheet is silk fibres.
8. Due to formation of hydrogen bonds peptide chains assume a secondary structure.

Question 18.
Explain the tertiary and quaternary structure of protein with example.
Answer:
Tertiary structure:

1. In tertiary structure the peptide chains are much looped, twisted and folded back on themselves due to formation of disulphide bonds.
2. Such loops and bends give the protein a tertiary structure.
3. E.g. Myoglobin, enzymes.

Quaternary structure:
1. When a protein has more than two polypeptide subunits their arrangement in space is called quaternary structure.
2. E.g. Haemoglobin.

Question 19.
Write a note on properties of protein.
Answer:
Properties of proteins are as follows:

1. Proteins are extremely reactive and highly specific in behaviour.
2. Proteins are amphoteric in nature i.e. they act as both acids and bases.
3. The behaviour of proteins is strongly influenced by pH.
4. Like amino acids, proteins are dipolar ions at the isoelectric point i.e. the sum of the positive charges is equal to the sum of the negative charges and the net charge is zero.
5. The ionic groups of a protein are contributed by the side chains of the polyfunctional amino acids.
6. A protein consists of more basic amino acids such as lysine and arginine exist as a cation at the physiological pH of 7.4. Such proteins are called basic proteins.
7. Histones of nucleoproteins are basic proteins.
8. A protein rich in acidic amino acids exists as an anion at the physiological pH. Such proteins are called acidic proteins.
9. Most of the blood proteins are acidic proteins.

Question 20.
Mention the findings of Feulgen.
Answer:
1. In 1924, Feulgen showed that chromosomes contain DNA.
2. He found that nucleic acids contain two pyrimidine (cytosine and thymine) and two purine (adenine and guanine) bases.

Question 21.
What were the findings of Wilkins and coworkers?
Answer:
The findings of Wilkins and coworkers were as follows:

1. Purine and pyrimidine bases are placed regularly along the DNA molecules at a distance of 3.4 A.
2. DNA (Deoxyribonucleotide) is composed of sugar molecule (a pentose sugar of deoxyribose type), phosphoric acid (phosphates when in chemical combination), nitrogen containing bases (nitrogen containing organic ring compounds).
3. Bases are of two types: Pyrimidine bases and purine bases.
4. Pyrimidine bases are single ring (monocyclic) nitrogenous bases. Cytosine, Thymine and uracil are pyrimidines.
5. Purine are double ring (dicyclic) nitrogenous bases. Adenine and guanine are purines.

Question 22.
Chargaff analyzed the composition of DNA from various sources. Mention what were his implications from all his experiments.
Answer:
Implications proposed by Erwin Chargaff:
1. Purine and pyrimidine always occur in equal amount in DNA.
2. The base ratio i.e. A+T/G+C may vary in the DNA of different groups of animals and plants but the ratio remains constant for particular species.

Question 23.
Describe the structure of DNA.
Answer:

1. DNA is a long chain made up of alternate sugar and phosphate groups. The sugar present in DNA is always a deoxyribose attached to a phosphate group. So, it forms a regular, repeating phosphate sugar sequence.
2. A base is attached to sugar -phosphate chain. Together this unit which consist of sugar, phosphate and a base is called nucleotide.
3. The nitrogenous base and a sugar of a nucleotide form a molecule called nucleoside. It lacks phosphate group. Four types of nucleoside are found in DNA molecule.
4. In a nucleoside, nitrogenous base is attached to the first carbon atom (C-1) of the sugar and when a phosphate group gets attached with that of the carbon (C-5) atom of the sugar molecule a nucleotide molecule is formed.
5. A single strand of DNA consists of several thousands of nucleotides one above the other.
6. The phosphate group of the lower nucleotide attached with the 5th carbon atom of the deoxyribose sugar forms phospho-di-ester bond with that of the 3rd carbon atom of the deoxyribose sugar of the nucleotide placed just above it.
7. Single long chain of polynucleotides of DNA consists of one end with sugar molecules not connected with another nucleotide having C-3 carbon which is not connected with phosphate group, similarly the other end having C-5 of the sugar is not connected with any phosphate group. These two ends of the polynucleotide chain are called as 3′ and 5′ ends respectively.
8. The single polynucleotide strand of DNA is not straight but helical in shape.
9. The DNA molecule consists of such two helical polynucleotide chains which are complementary to each other.
10. The two complementary polynucleotide chains of DNA are held together by the weak hydrogen bonds.
11. Adenine always pairs with thymine, and guanine with cytosine (a pyrimidine with a purine).
12. Adenine-thymine pair consists of two hydrogen bonds and guanine-cytosine pair consists of three hydrogen bonds (Thus, if the sequence of bases of a polynucleotide chain is known, that of the other can be determined).

Question 24.
Draw the structures of nitrogen bases in nucleic acid.
Answer:

Question 25.
Describe the structure of RNA.
Answer:

1. The other nucleic acid found in living organisms is Ribose nucleic acid.
2. In most of the organisms it is not found to be hereditary material but in certain organisms like tobacco mosaic virus, it is the hereditary material.
3. Like DNA, ribose nucleic acid also consists of polynucleotide chain with the difference that it consists of single strand. Exceptions are Reovirus and wound tumor virus where RNA is double stranded.
4. The nucleotides of RNA have ribose sugar instead of the deoxyribose sugar as in the case of DNA.
5. In case of RNA, Uracil substitutes thymine of DNA.
6. Purine, pyrimidine equality is not found in RNA molecule because of its single stranded structure.
7. RNA strand is usually found folded upon itself in certain regions or entirely. These folding helps in stability of the RNA molecule.
8. Most of the RNA polynucleotide chains start either with adenine or guanine.
9. Three types of cellular RNAs have been distinguished:
   1. messenger RNA (mRNA) or template RNA,
   2. ribosomal RNA (rRNA),
   3. transfer RNA (tRNA) or soluble RNA.

Question 26.
Observe the following figure and name the type of bond shown by arrow in the structure.

Answer:
The type of bond shown in the diagram is hydrogen bond.

Question 27.
What would have happened if there were no enzymes in the body?
Answer:
If enzymes were absent in the body, either the reactions would not occur or if they occur they would occur at a very slow rate.

Question 28.
How many reactions are catalyzed by an enzyme?
Answer:
Each enzyme catalyzes only one reaction.

Question 29.
What is a substrate?
Answer:
The substance upon which an enzyme acts is termed as the substrate.

Question 30.
What is endo-enzyines? Give examples.
Answer:
The enzymes which act within the cell in which they are synthesized are known as endo-enzymes E.g., enzymes produced in the chloroplast and mitochondria.

Question 31.
What are exo-enzymes?
Answer:
1. The enzymes which act outside the cell of which they are synthesized are known as exo-enzymes. E.g. enzymes released by many fungi.
2. These enzymes, synthesized by living cell, retain their catalytic property even when extracted from cells.

Question 32.
How are enzymes categorised?
Answer:
On basis of chemical composition enzymes are categorised:
1. Purely proteinaceous enzymes: e.g. Proteases that spilt protein
2. Conjugated enzymes: enzymes are made up of a protein to which a non-protein prosthetic group is attached.

Question 33.
What is a prosthetic group ? What w ill happen if it is removed?
Answer:
1. Prosthetic group is non-protein in nature and is attached to the protein component of enzyme by chemical bonds.
2. It is not removed by hydrolysis.
3. If the prosthetic group is removed the protein part of the enzyme becomes inactive.

Question 34.
What are coenzymes?
Answer:
1. Enzymes require certain organic compounds for their activity.
2. The organic compounds that are tightly attached to the protein part are called coenzymes.
3. E.g. Nicotinamaide adenine dinucleotide (NAD), Flavin mononucleotide (FMN).

Question 35.
What are co-factors?
Answer:
1. Enzymes require certain inorganic ions for their activity.
2. The inorganic ions which are loosely attached to the protein part are called co-factors.
E.g. Magnesium, copper, zinc, iron, manganese etc.
[Note: Apoenzyme (protein part) and co-factor together form a complete catalytically active enzyme which is known as holoenzyme. The co-factors are of two types; metal ions and coenzymes. A coenzyme or metal ion that is very tightly or even covalently bound to the enzyme protein is known as a prosthetic group.]

Question 36.
Complete the analogy.
Iron (Fe): Catalase: Manganese (Mn):
Answer:
Peptidase

Question 37.
Give examples of coenzymes and cofactors.
Answer:
1. Nicotinamaide adenine dinucleotide (NAD), Flavin mononucleotide (FMN).
2. Magnesium, copper, zinc, iron, manganese etc.

Question 38.
How are enzymes named?
Answer:

1. Enzymes are named by adding the suffix- ‘ase’ to the name of the substrate on which they act e.g. protease, sucrase, nuclease etc. which break up proteins, sucrose and nucleic acids respectively.
2. The enzymes can be named according to the type of function they perform.
   For e.g., dehydrogenase remove hydrogen, carboxylase add CO; decarboxylases remove C0₂, oxidases helping in oxidation.
3. Some enzymes are named according to the source from which they are obtained.
   For e.g., papain from papaya, bromelain from the member of Bromeliaceae family, pineapple.
4. According to international code of enzyme nomenclature, the name of each enzyme ends with an -ase and consists of double name!
5. The first name indicates the nature of substrate upon which the enzyme acts and the second name indicates the reaction catalyzed.

For e.g., pyruvic decarboxylase catalyses the removal of C0₂ from the substrate pyruvic acid.
Similarly, the enzyme glutamate pyruvate transaminase catalyses the transfer of an amino group from the substrate glutamate to another substrate pyruvate.

Question 39.
Explain in detail the mechanism of enzyme action. Write a note on model proposed by Emil Fischer for mechanism of enzyme action.
Answer:
1. The basic mechanism by which enzymes catalyze chemical reactions begins with the binding of the substrate (or substrates) to the active site on the enzyme.
2. The active site is the specific region of the enzyme which combines with the substrate.
3. The binding of the substrate to the enzyme causes changes in the distribution of electrons in the chemical bonds of the substrate and ultimately causes the reactions that lead to the formation of products.
4. The products are released from the enzyme surface to regenerate the enzyme for another reaction cycle.

5. Lock and Key model proposed by Emil Fischer: i. Proteinaceous Nature:
All enzymes are basically made up of protein.

Question 40.
Describe the concept of metabolism.
Answer:

1. Metabolism is the sum of the chemical reactions that take place within each cell of a living organism and provide energy for vital processes and for synthesizing new organic material.
2. It involves continuous process of breakdown and synthesis of biomolecules through chemical reactions.
3. Each of the metabolic reaction results in a transformation of biomolecules.
4. Most of these metabolic reactions do not occur in isolation but are always linked with some other reactions.
5. In cells, metabolism involves two following types of pathways:

a. Catabolic pathways
This involves formation of simpler structure from a complex biomolecule.
For e.g. when we eat wheat, bread or chapati, our gastrointestinal tract digests (hydrolyses) the starch to glucose units with help of enzymes and releases energy in form of ATP (Adenosine triphosphate).

b. Anabolic pathway
It is also called as biosynthetic pathway that involves formation of a more complex biomolecules from a simpler structure
Fone.g., synthesis of glycogen from glucose and protein from amino acids. These pathways consume energy.

Question 41.
Draw a flowchart showing catabolic and anabolic reactions.
Answer:

Question 42.
Write a short note on secondary metabolites.
Answer:

1. Secondary metabolites are small organic molecules produced by organisms that are not essential for their growth, development and reproduction.
2. Several types of bacteria, fungi and plants produce secondary metabolites.
3. Secondary metabolites can be classified on the basis of chemical structure (e.g. SMs containing rings, sugar), composition (with or without nitrogen), their solubility in various solvents, or the pathway by which they are synthesized (e.g. phenylpropanoid produces tannins).
4. A simple way of classifying secondary metabolites includes three main groups such as:
   • Terpenes: Made from mevalonic acid that is composed mainly of carbon and hydrogen
   • Phenolics: Made from simple sugars containing benzene rings, hydrogen and oxygen.
   • Nitrogen-containing compounds: Extremely diverse class may also contain sulphur.

Question 43.
Fill in the blanks.

1. Living organism have _________ as the basic structural and functional unit.
2. The cells have _______ containing numerous chemical molecules, the biomolecules.
3. ________ are used very quickly by cells but if a cell is not in need of all the energy released immediately then it may get stored.
4. By ________ reaction monosaccharide is converted to disaccharide.
5. The balance between catabolism and anabolism maintain _______ in the cell as well as in the whole body.

Answer:

1. Cell
2. Protoplasm
3. monosaccharides
4. Condensation reaction
5. Homeostasis

Question 44.
Apply Your Knowledge:

Question 1.
While performing an experiment, to understand effect of pH on enzyme activity, a student prepared
solution of varied pH. He observed that enzyme activity is maximum at a particular range of pH.
What is the reason for its maximum activity at a particular range of pH? What would be the effect on enzyme activity if strong acid or strong base is added?
Answer:
The enzymes are highly specific to pH and remain active within particular range of pH only. Hence, exhibit maximum activity only at particular range of pH. When strong acid or strong base is added in the reaction the enzyme activity is inhibited as most of the enzymes are denatured.

Question 2.
When a compound ‘x’ is added to a chemical solution containing enzyme and substrate, the enzymatic activity stops. What could be the nature of compound ‘x’?
Answer:
Compound ‘x’ could be either competitive or non-competitive inhibitor.

Question 45.
Quick Review

Question 46.
Exercise:

Question 1.
Draw a flow chart of biomolecules in living system.
Answer:
Refer Quick Review

Question 2.
Explain what is biochemistry?
Answer:
1. Biochemistry is biological chemistry that provides us the idea of the chemistry of living organisms and molecular basis for changes taking place in plants, animals and microbial cells.
2. It develops the foundation for understanding all biological processes and communication within and between cells as well as chemical basis of inheritance and diseases in animals and plants.

Question 3.
Mention the basic macromolecules present in the living organism.
Answer:
Polysaccharides (carbohydrate) polymer of monosaccharide, polypeptides (proteins) polymer of amino acids and polynucleotides (nucleic acids) polymer of nucleotides are the three basic macromolecule present in the living organisms.

Question 4.
Write a note on monosaccharides.
Answer:
Monosaccharides:
a. Monosaccharides are the simplest sugars having crystalline structure, sweet taste and soluble in water.
b. They cannot be further hydrolyzed into smaller molecules.
c. They are the building blocks or monomers of complex carbohydrates.
d. They have the general molecular formula (CH20)n, where n can be 3, 4, 5, 6 and 7.
e. They can be classified as triose, tetrose, pentose, etc.
f. Monosaccharides containing the aldehyde (-CHO) group are classified as aldoses e.g. glucose, xylose, and those with a ketone(-C=0) group are classified as ketoses. E.g. ribulose, fructose.

Question 5.
Explain the absorption of disaccharides through the cell membrane.
Answer:
1. Disaccharides are soluble in water but they are too big to pass through the cell membrane by diffusion.
2. They are broken down in the small intestine during digestion.
3. Thus, formed monosaccharides then pass into the blood and through cell membranes into the cells.

Question 6.
Draw the structure of amylose.
Answer:
Starch:
a. Starch is a stored food in the plants.
b. Starch contains two types of glucose polymer: amylose and amylopectin.
c. Both are made from a-glucose.
d. Amylose is an unbranched polymer of a-glucose.
e. The molecules coil into a helical structure.
f. It foims a colloidal suspension in hot water.
g. Amylopectin is a branched polymer of a-glucose.
h. It is completely insoluble in water.

Question 7.
Write the significance of carbohydrates.
Answer:
Significances of carbohydrates are as follows:

1. Carbohydrates provide energy for metabolism.
2. Glucose is the main substrate for ATP synthesis.
3. Lactose, a disaccharide present in the milk provides energy to babies.
4. Polysaccharide serves as a structural component of cell membrane, cell wall and reserved food as starch and glycogen.

Question 8.
What is glycosidic bond?
Answer:
Oligosaccharides:
a. A carbohydrate polymer comprising of two to six monosaccharide molecules is called oligosaccharide.
b. They are linked together by glycosidic bond.
c. They are classified on the basis of monosaccharide units:
Disaccharides: These are the sugars containing two monosaccharide units and can be further hydrolysed into smaller components. E.g.: Sucrose, maltose, lactose, etc.
Trisaccharides: These contain three monomers. E.g. Raffmose.
Tetrasaccharides: These contain four monomers. E.g.: Stachyose.

Glycosidic bond:
a. Glycosidic bond is a covalent bond that forms a linkage between two monosaccharides by a dehydration reaction.
b. It is formed when a hydroxyl group of one sugar reacts with the anomeric carbon of the other.
c. Glycosidic bonds are readily hydrolyzed by acid but resist cleavage by base.
d. There are two types of glycosidic bonds: a-glycosidic bond and P-glycosidic bond.

Question 9.
What are saturated fatty acids?
Answer:
1. Saturated fatty acids: They contain single chain of carbon atoms with single bonds.
E.g. Palmitic acid, stearic acid
2. Unsaturated fatty acids: They contain one or more double bonds between the carbon atoms of the hydrocarbon chain.
a. Simple lipids: These are esters of fatty acids with various alcohols.
E.g. Fats, wax.
b. Compound lipids: These are ester of fatty acids containing other groups like phosphate (Phospholipids), sugar (glycolipids), etc.
E.g. Lecithin
c. Sterols: They are derived lipids. They are composed of fused hydrocarbon rings (steroid nucleus) and a long hydrocarbon side chain.
E.g. Cholesterol, phytosterols.

Question 10.
Write a note on simple lipids.
Answer:
Lipids are classified into three main types:
Simple lipids:
a. These are esters of fatty acids with various alcohols. Fats and waxes are simple lipids.
b. Fats are esters of fatty acids with glycerol (CH₂OH-CHOH-CH₂OH).
c. Triglycerides are three molecules of fatty acids and one molecule of glycerol.
d. Unsaturated fats are liquid at room temperature and are called oils. Unsaturated fatty acids are hydrogenated to produce fats e.g. Vanaspati ghee.

Question 11.
Write a note on derived lipids.
Answer:
Derived Lipids:
a. They are composed of fused hydrocarbon rings (steroid nucleus) and a long hydrocarbon side chain.
b. One of the most common sterols is cholesterol.
Biological significance:
a. It is widely distributed in all cells of the animal body, but particularly in nervous tissue.
b. Cholesterol exists either free or as cholesterol ester.
c. Adrenocorticoids, sex hormones (progesterone, testosterone) and vitamin D are synthesized from cholesterol.
d. Cholesterol is not found in plants.
e. Sterols exist as phytosterols in plants.
f. Yam Plant (Dioscorea) produces a steroid compound called diosgenin. It is used in the manufacture of antifertility pills, i.e. birth control pills.

Question 12.
What are compound lipids? Mention their biological significance.
Answer:
Compound lipids:
a. These are ester of fatty acids containing other groups like phosphate (Phospholipids), sugar (glycolipids), etc.
b. They contain a molecule of glycerol, two molecules of fatty acids and a phosphate group or simple sugar.
c. Some phospholipids such as lecithin also have a nitrogenous compound attached to the phosphate group.
d. Phospholipids have both hydrophilic polar groups (phosphate and nitrogenous group) and hydrophobic non-polar groups (hydrocarbon chains of fatty acids).
e. Glycolipids contain glycerol, fatty acids, simple sugars such as galactose. They are also called cerebrosides.
Biological significance:
a. Phospholipids contribute in the formation of cell membrane.
b. Large amounts of glycolipids are found in the brain white matter and myelin sheath.

Question 13.
Explain the classification of proteins based on their chemical composition.
Answer:
On the basis of structure, proteins are classified into three categories:
1. Simple proteins:
a. Simple proteins on hydrolysis yield only amino acids.
b. These are soluble in one or more solvents.
c. Simple proteins may be soluble in water.
d. Histones of nucleoproteins are soluble in water.
e. Globular molecules of histones are not coagulated by heat.
f. Albumins are also soluble in water but they get coagulated on heating.
g. Albumins are widely distributed e.g. egg albumin, serum albumin and legumelin of pulses are albumins.
Importance: They are involved in structural components; they also act as a storage kind of protein.
Some are associated with nucleic acids in nucleoproteins of cell.

2. Conjugated proteins:
a. Conjugated proteins consist of a simple protein united with some non-protein substance.
b. The non-protein group is called prosthetic group e.g. haemoglobin.
c. Globin is the protein and the iron containing pigment haem is the prosthetic group.
d. Similarly, nucleoproteins have nucleic acids.
e. Proteins are classified as glycoproteins and mucoproteins.
f. Mucoproteins are carbohydrate-protein complexes e.g. mucin of saliva and heparin of blood.
g. Lipoproteins are lipid-protein complexes e.g. conjugate protein found in brain, plasma membrane, milk etc. Importance: They are involved in structural components of cell membranes and organelles.
They also act as a transporter.
Some conjugated proteins are important in electron transport chain in respiration.

3. Derived proteins:
a. These proteins are not found in nature as such.
b. These proteins are derived from native protein molecules on hydrolysis.
c. Metaproteins, peptones are derived proteins.
Importance: They act as a precursor for many molecules which are essential for life.

Question 14.
What is peptide bond? Explain its formation.
Answer:
1. The covalent bond that links the two amino acids is called a peptide bond.
2. Peptide bond is formed by condensation reaction.

Question 15.
Mention the examples of simple proteins and write their significance.
Answer:
Examples of simple proteins are: E.g.: Albumins and histones.
Significance:
1. Albumin:
a. % It is the main protein in the blood.
b. It maintains the pressure in the blood vessels.
c. It helps in transportation of substances like hormone and drugs in the body.
2. Histones:
a. It is the chief protein of chromatin.
b. They are involved in packaging of DNA into structural units called nucleosomes.

Question 16.
What is nucleotide?
Answer:
Nucleotide is a unit which consists of a sugar, phosphate and a base. Nucleotides are basic units of nucleic acids.

Question 17.
Write a note on structure of DNA molecule proposed by Watson and Crick.
Answer:
1. DNA is a long chain made up of alternate sugar and phosphate groups. The sugar present in DNA is always a deoxyribose attached to a phosphate group. So, it forms a regular, repeating phosphate sugar sequence.
2. A base is attached to sugar -phosphate chain. Together this unit which consist of sugar, phosphate and a base is called nucleotide.
3. The nitrogenous base and a sugar of a nucleotide form a molecule called nucleoside. It lacks phosphate group. Four types of nucleoside are found in DNA molecule.
4. In a nucleoside, nitrogenous base is attached to the first carbon atom (C-1) of the sugar and when a phosphate group gets attached with that of the carbon (C-5) atom of the sugar molecule a nucleotide molecule is formed.
5. A single strand of DNA consists of several thousands of nucleotides one above the other.
6. The phosphate group of the lower nucleotide attached with the 5th carbon atom of the deoxyribose sugar forms phospho-di-ester bond with that of the 3rd carbon atom of the deoxyribose sugar of the nucleotide placed just above it.
7. Single long chain of polynucleotides of DNA consists of one end with sugar molecules not connected with another nucleotide having C-3 carbon which is not connected with phosphate group, similarly the other end having C-5 of the sugar is not connected with any phosphate group. These two ends of the polynucleotide chain are called as 3′ and 5′ ends respectively.
8. The single polynucleotide strand of DNA is not straight but helical in shape.
9. The DNA molecule consists of such two helical polynucleotide chains which are complementary to each other.
10. The two complementary polynucleotide chains of DNA are held together by the weak hydrogen bonds.
11. Adenine always pairs with thymine, and guanine with cytosine (a pyrimidine with a purine).
12. Adenine-thymine pair consists of two hydrogen bonds and guanine-cytosine pair consists of three hydrogen bonds (Thus, if the sequence of bases of a polynucleotide chain is known, that of the other can be determined).

1. According to Watson and Crick, DNA molecule consists of two strands twisted around each other in the form of a double helix.
2. The two strands i.e. polynucleotide chains are supposed to be in opposite direction so end of one chain having 3′ lies beside the 5′ end of the other.
3. One turn of the double helix of the DNA measures about 34A.
4. It consists paired nucleotides and the distance between two neighboring pair nucleotides is 3.4A.
5. The diameter of the DNA molecule has been found be 20A.

Question 18.
What is the function of ribosomal RNA?
Answer:
Ribosomal RNA (rRNA):
a. rRNA was discovered by Kurland in 1960.
b. It forms 50-60% part of ribosomes.
c. It accounts 80-90% of the cellular RNA.
d. It is synthesized in nucleus.
e. It gets coiled at various places due to intrachain complementary base pairing.
Role of ribosomal RNA: It provides proper binding site for m-RNA during protein synthesis.

Question 19.
Write a short note on m-RNA.
Answer:
Messenger RNA (mRNA):
a. It is a linear polynucleotide.
b. It accounts 3% of cellular RNA.
c. Its molecular weight is several million. , d. mRNA molecule carrying information to form a complete polypeptide chain is called cistron.
e. Size of mRNA is related to the size of message it contains.
f. Synthesis of mRNA begins at 5’ end of DNA strand and terminates at 3’ end.

Role of messenger RNA:
It carries genetic information from DNA to ribosomes, which are the sites of protein synthesis.

Question 20.
Write a note on types of non-genetic RNA.
Answer:
There are three types of cellular RNAs:
1. messenger RNA (mRNA),
2. ribosomal RNA (rRNA),
3. transfer RNA (tRNA). ‘

1. Messenger RNA (mRNA):
a. It is a linear polynucleotide.
b. It accounts 3% of cellular RNA.
c. Its molecular weight is several million. , d. mRNA molecule carrying information to form a complete polypeptide chain is called cistron.
e. Size of mRNA is related to the size of message it contains.
f. Synthesis of mRNA begins at 5’ end of DNA strand and terminates at 3’ end.

Role of messenger RNA:
It carries genetic information from DNA to ribosomes, which are the sites of protein synthesis.

2. Ribosomal RNA (rRNA):
a. rRNA was discovered by Kurland in 1960.
b. It forms 50-60% part of ribosomes.
c. It accounts 80-90% of the cellular RNA.
d. It is synthesized in nucleus.
e. It gets coiled at various places due to intrachain complementary base pairing.
Role of ribosomal RNA: It provides proper binding site for m-RNA during protein synthesis.

3. Transfer RNA (tRNA):
a. These molecules are much smaller consisting of 70-80 nucleotides.
b. Due to presence of complementary base pairing at various places, it is shaped like clover-leaf.
c. Each tRNA can pick up particular amino acid.
d. Following four parts can be recognized on tRNA
1. DHU arm (Dihydroxyuracil loop/ amino acid recognition site
2. Amino acid binding site
3. Anticodon loop / codon recognition site
4. Ribosome recognition site.
e. In the anticodon loop of tRNA, three unpaired nucleotides are present called as anticodon which pair with codon present on mRNA.
f. The specific amino acids are attached at the 3’ end in acceptor stem of clover leaf of tRNA.
Role of transfer RNA: It helps in elongation of polypeptide chain during the process called translation.

Question 21.
What are co-factors? Give examples.
Answer:

1. Enzymes require certain inorganic ions for their activity.
2. The inorganic ions which are loosely attached to the protein part are called co-factors.
3. E.g. Magnesium, copper, zinc, iron, manganese etc.

[Note: Apoenzyme (protein part) and co-factor together form a complete catalytically active enzyme which is known as holoenzyme. The co-factors are of two types; metal ions and coenzymes. A coenzyme or metal ion that is very tightly or even covalently bound to the enzyme protein is known as a prosthetic group.]

Question 22.
Describe the important properties of enzymes.
Answer:
1. Proteinaceous Nature:
All enzymes are basically made up of protein.

2. Three-Dimensional conformation:
a. All enzymes have specific 3-dimensional conformation.
b. They have one or more active sites to which substrate (reactant) combines.
c. The points of active site where the substrate joins with the enzyme is called substrate binding site.

3. Catalytic property:
a. Enzymes are like inorganic catalysts and influence the speed of biochemical reactions but themselves remain unchanged.
b. After completion of the reaction and release of the product they remain active to catalyze again.
c. A small quantity of enzymes can catalyze the transformation of a very large quantity of the substrate
into an end product.
d. For example, sucrase can hydrolyze 100000 times of sucrose as compared with its own weight.

4. Specificity of action:
a. The ability of an enzyme to catalyze one specific reaction and essentially no other is perhaps its most significant property. Each enzyme acts upon a specific substrate or a specific group of substrates.
b. Enzymes are very sensitive to temperature and pH.
c. Each enzyme exhibits its highest activity at a specific pH i.e. optimum pH.
d. Any increase or decrease in pH causes decline in enzyme activity e.g. enzyme pepsin (secreted in stomach)shows highest activity at an optimum pH of 2 (acidic)

5. Temperature:
a. Enzymes are destroyed at higher temperature of 60-70°C or below, they are not destroyed but become inactive.
b. This inactive state is temporary and the enzyme can become active at suitable temperature.
c. Most of the enzymes work at an optimum temperature between 20°C and 35°C.

There are two types of models:
1. Lock and Key model:
a. Lock and Key model was first postulated in 1894 by Emil Fischer.
b. This model explains the specific action of an enzyme with a single substrate.
c. In this model, lock is the enzyme and key is the substrate.
d. The correctly sized key (substrate) fits into the key hole (active site) of the lock (enzyme).

2. Induced Fit model (Flexible Model):
a. Induced Fit model was first proposed in 1959 by Koshland.
b. This model states that approach of a substrate induces a conformational change in the enzyme.
c. It is the more accepted model to understand mode of action of enzyme.
d. The induced fit model shows that enzymes are rather flexible structures in which the active site continually reshapes by its interactions with the substrate until the time the substrate is completely bound to it.
e. It is also the point at which the final form and shape of the enzyme is determined.
[Note: Temperature is a factor affecting enzyme activity and not a property of enzyme.]

Question 23.
Explain the classification enzymes and mention the example of each class.
Answer:
1. Enzymes are biological macromolecules which act as a catalyst and accelerates the reaction in the body.
2. Enzymes are classified into six classes:
a. Oxidoreductases: These enzymes catalyze oxidation and reduction reactions by the transfer of hydrogen and/or oxygen, e.g. alcohol dehydrogenase
b. Transferases: These enzymes catalyse the transfer of certain groups between two molecules, e.g. glucokinase
c. Hydrolases: These enzymes catalyse hydrolytic reactions. This class includes amylases, proteases, lipases etc. e.g. Sucrase
d. Lyases: These enzymes are involved in elimination reactions resulting in the removal of a group of atoms from substrate molecule to leave a double bond. It includes aldolases, decarboxylases, and dehydratases, e.g. fumarate hydratase.
e. Isomerases: These enzymes catalyze structural rearrangements within a molecule. Their nomenclature is based on the type of isomerism. Thus, these enzymes are identified as racemases, epimerases, isomerases, mutases, e.g. xylose isomerase.
f. Ligases or Synthetases: These are the enzymes which catalyze the covalent linkage of the molecules utilizing the energy obtained from hydrolysis of an energy-rich compound like ATP, GTP e.g. glutathione synthetase, Pyruvate carboxylase.

Question 24.
Enlist the factors affecting the activity of enzymes.
Answer:
The factors affecting the enzyme activity are as follows:
1. Concentration of substrate:
a. Increase in the substrate concentration gradually increases the velocity of enzyme activity within the limited range of substrate levels.
b. A rectangular hyperbola is obtained when velocity is plotted against the substrate concentration.
c. Three distinct phases (A, B and C) of the reaction are observed in the graph.
Where V = Measured velocity, V_max = Maximum velocity, S = Substrate concentration,
K_m = Michaelis-Menten constant.
d. K_m or the Michaelis-Menten constant is defined as the substrate concentration (expressed in moles/lit) to produce half of maximum velocity in an enzyme catalyzed reaction.
e. It indicates that half of the enzyme molecules (i.e. 50%) are bound with the substrate molecules when the substrate concentration equals the Km value.
f. K_m value is a constant and a characteristic feature of a given enzyme.
g. It is a representative for measuring the strength of ES complex.
h. A low K_m value indicates a strong affinity between enzyme and substrate, whereas a high Km value reflects a weak affinity between them.
i. For majority of enzymes, the K_m values are in the range of 10_-5 to 10_-2 moles.

2. Enzyme Concentration:
a. The rate of an enzymatic reaction is directly proportional to the concentration of the substrate.
b. The rate of reaction is also directly proportional to the square root of the concentration of enzymes.
c. It means that the rate of reaction also increases with the increasing concentration of enzyme and the rate of reaction can also decrease by decreasing the concentration of enzyme.

3. Temperature:
a. The temperature at which the enzymes show maximum activity is called Optimum temperature.
b. The rate of chemical reaction is increased by a rise in temperature but this is true only over a limited range of temperature.
c. Enzymes rapidly denature at temperature above 40°C.
d. The activity of enzymes is reduced at low temperature.
e. The enzymatic reaction occurs best at or around 37°C which is the average normal body temperature in homeotherms.

4. Effect of pH:
a. The pH at which an enzyme catalyzes the reaction at the maximum rate is known as optimum pH.
b. The enzyme cannot perform its function beyond the range of its pH value.

5. Other substances:
a. The enzyme action is also increased or decreased in the presence of some other substances such as co-enzymes, activators and inhibitors.
b. Most of the enzymes are combination of a co-enzyme and an apo-enzyme.
c. Activators are the inorganic substances which increase the enzyme activity.
d. Inhibitor is the substance which reduces the enzyme activity.

Question 25.
With the help of lock and key theory explain the mechanism of enzyme action.
Answer:
1. Proteinaceous Nature:
All enzymes are basically made up of protein.

2. Three-Dimensional conformation:
a. All enzymes have specific 3-dimensional conformation.
b. They have one or more active sites to which substrate (reactant) combines.
c. The points of active site where the substrate joins with the enzyme is called substrate binding site.

3. Catalytic property:
a. Enzymes are like inorganic catalysts and influence the speed of biochemical reactions but themselves remain unchanged.
b. After completion of the reaction and release of the product they remain active to catalyze again.
c. A small quantity of enzymes can catalyze the transformation of a very large quantity of the substrate
into an end product.
d. For example, sucrase can hydrolyze 100000 times of sucrose as compared with its own weight.

4. Specificity of action:
a. The ability of an enzyme to catalyze one specific reaction and essentially no other is perhaps its most significant property. Each enzyme acts upon a specific substrate or a specific group of substrates.
b. Enzymes are very sensitive to temperature and pH.
c. Each enzyme exhibits its highest activity at a specific pH i.e. optimum pH.
d. Any increase or decrease in pH causes decline in enzyme activity e.g. enzyme pepsin (secreted in stomach)shows highest activity at an optimum pH of 2 (acidic)

5. Temperature:
a. Enzymes are destroyed at higher temperature of 60-70°C or below, they are not destroyed but become inactive.
b. This inactive state is temporary and the enzyme can become active at suitable temperature.
c. Most of the enzymes work at an optimum temperature between 20°C and 35°C.

There are two types of models:
1. Lock and Key model:
a. Lock and Key model was first postulated in 1894 by Emil Fischer.
b. This model explains the specific action of an enzyme with a single substrate.
c. In this model, lock is the enzyme and key is the substrate.
d. The correctly sized key (substrate) fits into the key hole (active site) of the lock (enzyme).

Question 26.
With the help of suitable examples give any three classes of enzymes.
Answer:
a. Oxidoreductases: These enzymes catalyze oxidation and reduction reactions by the transfer of hydrogen and/or oxygen, e.g. alcohol dehydrogenase
b. Transferases: These enzymes catalyse the transfer of certain groups between two molecules, e.g. glucokinase
c. Hydrolases: These enzymes catalyse hydrolytic reactions. This class includes amylases, proteases, lipases etc. e.g. Sucrase

Question 27.
Following graph represents the effect of substrate concentration on enzyme activity. Identify ‘X’ and ‘Y’ Write proper explanation of the process.

Answer:
The factors affecting the enzyme activity are as follows:
1. Concentration of substrate:
a. Increase in the substrate concentration gradually increases the velocity of enzyme activity within the limited range of substrate levels.
b. A rectangular hyperbola is obtained when velocity is plotted against the substrate concentration.
c. Three distinct phases (A, B and C) of the reaction are observed in the graph.
Where V = Measured velocity, V_max = Maximum velocity, S = Substrate concentration,
K_m = Michaelis-Menten constant.
d. K_m or the Michaelis-Menten constant is defined as the substrate concentration (expressed in moles/lit) to produce half of maximum velocity in an enzyme catalyzed reaction.
e. It indicates that half of the enzyme molecules (i.e. 50%) are bound with the substrate molecules when the substrate concentration equals the Km value.
f. K_m value is a constant and a characteristic feature of a given enzyme.
g. It is a representative for measuring the strength of ES complex.
h. A low K_m value indicates a strong affinity between enzyme and substrate, whereas a high Km value reflects a weak affinity between them.
i. For majority of enzymes, the K_m values are in the range of 10_-5 to 10_-2 moles.

Question 28.
Explain the concept of metabolism.
Answer:

1. Metabolism is the sum of the chemical reactions that take place within each cell of a living organism and provide energy for vital processes and for synthesizing new organic material.
2. It involves continuous process of breakdown and synthesis of biomolecules through chemical reactions.
3. Each of the metabolic reaction results in a transformation of biomolecules.
4. Most of these metabolic reactions do not occur in isolation but are always linked with some other reactions.
5. In cells, metabolism involves two following types of pathways:

a. Catabolic pathways
This involves formation of simpler structure from a complex biomolecule.
For e.g. when we eat wheat, bread or chapati, our gastrointestinal tract digests (hydrolyses) the starch to glucose units with help of enzymes and releases energy in form of ATP (Adenosine triphosphate).

b. Anabolic pathway
It is also called as biosynthetic pathway that involves formation of a more complex biomolecules from a simpler structure
Fone.g., synthesis of glycogen from glucose and protein from amino acids. These pathways consume energy.

Question 29.
Distinguish between Catabolic pathways and anabolic pathways.
Answer:
In cells, metabolism involves two following types of pathways:

a. Catabolic pathways
This involves formation of simpler structure from a complex biomolecule.
For e.g. when we eat wheat, bread or chapati, our gastrointestinal tract digests (hydrolyses) the starch to glucose units with help of enzymes and releases energy in form of ATP (Adenosine triphosphate).

b. Anabolic pathway
It is also called as biosynthetic pathway that involves formation of a more complex biomolecules from a simpler structure
Fone.g., synthesis of glycogen from glucose and protein from amino acids. These pathways consume energy.

Question 30.
Write the application of secondary metabolites.
Answer:

1. Drugs developed from secondary metabolites have been used to treat infectious diseases, cancer, hypertension and inflammation.
2. Morphine, the first alkaloid isolated from Papaver somniferum is used as pain reliver and cough suppressant.
3. Secondary metabolites like alkaloids, nicotine, cocaine and the terpenes, cannabinol are widely used for recreation and stimulation.
4. Flavours of secondary metabolites improve our food preferences.
5. Tannins are added to wines and chocolate for improving astringency.
6. Since most secondary metabolites have antibiotic property, they are also used as food preservatives.
7. Glucosinolates is a secondary metabolite which is naturally present in cabbage imparts a characteristic flavour and aroma because of nitrogen and sulphur-containing chemicals. It also offers protection to these plants from many pests.

Question 31.
Explain the formation of metabolic pool.
Answer:

1. Metabolism is the sum of the chemical reactions that take place within each cell of a living organism and provide energy for vital processes and for synthesizing new’ organic material.
2. Metabolic pool in the cell is formed due to glycolysis and Krebs cycle.
3. The catabolic chemical reaction of glycolysis and Krebs cycle provides ATP and biomolecules. These biomolecules form the metabolic pool of the cell.
4. These biomolecules can be utilized for synthesis of many important cellular components.
5. The metabolites can be added or withdrawn from the pool according to the need of the cell.

Question 32.
Explain the concept of metabolic pool.
Answer:
1. Metabolic pool is the reservoir of biomolecules in the cell on which enzymes can act to produce useful products as per the need of the cell.
2. The concept of metabolic pool is significant in cell biology because it allows one type of molecule to change into another type E.g. Carbohydrates can be converted to fats and vice-versa.

Question 33.
Multiple Choice Questions:

Question 1.
Most common constituents of organic compounds found in organims are
(A) C, H, O, P
(B) C, H, O
(C) C, H, N, P
(D) C, H, O, N, P
Answer:
(B) C, H, O

Question 2.
Carbohydrates are composed of
(A) carbon
(B) hydrogen
(C) oxygen
(D) all of these
Answer:
(D) all of these

Question 3.
In which of the following, the ratio of hydrogen and oxygen atoms is 2:1?
(A) proteins
(B) fats
(C) oil
(D) carbohydrates
Answer:
(D) carbohydrates

Question 4.
Which of the following do not give smaller sugar units on hydrolysis?
(A) Monosaccharides
(B) Disaccharides
(C) Polysaccharides
(D) Glycogen
Answer:
(A) Monosaccharides

Question 5.
The simplest monosaccharide made up of three carbons amongst the following is
(A) erythrose
(B) glucose
(C) glyceraldehyde
(D) ribose
Answer:
(C) glyceraldehyde

Question 6.
Deoxyribose sugar is an example of
(A) monosaccharide
(B) disaccharide
(C) polysaccharide
(D) simple protein
Answer:
(A) monosaccharide

Question 7.
Common examples of hexose sugar is/are
(A) glucose
(B) fructose
(C) erythrose
(D) both (A) and (B)
Answer:
(D) both (A) and (B)

Question 8.
If a compound contains 2 monosaccharides, then it is described as
(A) derived monosaccharide
(B) disaccharide
(C) polysaccharide
(D) pentose sugar
Answer:
(B) disaccharide

Question 9.
In a disaccharide, monomers are linked with each other through ________ bonds.
(A) peptide
(B) hydrogen
(C) glycosidic
(D) ester
Answer:
(C) glycosidic

Question 10.
A disaccharide that gives two molecules of glucose on hydrolysis is
(A) sucrose
(B) maltose
(C) lactose
(D) none of these
Answer:
(B) maltose

Question 11.
Sugar present in milk is
(A) fructose
(B) lactose
(C) galactose
(D) sucrose
Answer:
(B) lactose

Question 12.
Polysaccharides consist of
(A) two monosaccharide units
(B) eight monosaccharide units
(C) many monosaccharide units
(D) amino acids
Answer:
(C) many monosaccharide units

Question 13.
________ are water insoluble and small molecular weight compounds as compared to macromolecules.
(A) Lipids
(B) proteins
(C) carbohydrates
(D) nucleic acids.
Answer:
(A) Lipids

Question 14.
Simple lipids are esters of
(A) amino acids
(B) proteins
(C) phosphorus
(D) fatty acids with glycerol
Answer:
(D) fatty acids with glycerol

Question 15.
Fatty acids which do not contain double bond between carbon atoms are
(A) saturated fatty acids
(B) unsaturated fatty acids
(C) oleic and linoleic acids
(D) linoleic and linolenic acids
Answer:
(A) saturated fatty acids

Question 16.
Proteins are linear polymers of
(A) amino acids
(B) fatty acids
(C) monosaccharides
(D) nucleic acids
Answer:
(A) amino acids

Question 17.
Proteins are formed by the condensation of
(A) nucleic acids
(B) amino acids
(C) fatty acids
(D) carbohydrates
Answer:
(B) amino acids

Question 18.
Protein is
(A) micromolecule
(B) macromolecule
(C) soluble
(D) specific
Answer:
(B) macromolecule

Question 19.
Keratin is a ________ protein.
(A) transport
(B) protective
(C) structural
(D) storage
Answer:
(C) structural

Question 20.
A nucleotide contains
(A) sugar + phosphate
(B) N-base + phosphate
(C) sugar + nitrogenous base
(D) sugar + N-base + phosphate
Answer:
(D) sugar + N-base + phosphate

Question 21.
Nucleotides, the polymers of nucleic acid are joined together by __________ bond.
(A) Peptide
(B) Ester
(C) Phosphodiester
(D) Glycosidic
Answer:
(C) Phosphodiester

Question 22.
Find the odd one.
(A) Adenine
(B) Cytosine
(C) Thymine
(D) Uracil
Answer:
(D) Uracil

Question 23.
The two strands of DNA are
(A) similar in nature and complementary
(B) anti-parallel and complementary
(C) parallel and complementary
(D) basically, different in nature
Answer:
(B) anti-parallel and complementary

Question 24.
RNA is genetic material in
(A) bacteria
(B) cyanobacteria
(C) bacteriophages
(D) plant viruses
Answer:
(D) plant viruses

Question 25.
Which RNA is present in more amount in the cell?
(A) m-RNA
(B) t-RNA
(C) r-RNA
(D) not certain
Answer:
(C) r-RNA

Question 26.
Smallest RNA is
(A) t-RNA
(B) m-RNA
(C) r-RNA
(D) not specific
Answer:
(A) t-RNA

Question 27.
________ catalyze hydrolysis of ester, ether etc.
(A) Lyases
(B) Ligases
(C) Hydrolases
(D) Transferases
Answer:
(C) Hydrolases

Question 28.
_______ catalyze interconversions of geometric, optical and positional isomers.
(A) Transferases
(B) Ligases
(C) Oxidoreductase
(D) Isomerases
Answer:
(D) Isomerases

Question 29.
Metal cofactors are also known as?
(A) prosthetic group
(B) coenzyme
(C) activators
(D) inhibitors
Answer:
(C) activators

Question 30.
________ are also known as dehydrogenases.
(A) Oxidoreductases
(B) Ligases
(C) Lyases
(D) Transferases
Answer:
(A) Oxidoreductases

Question 31.
The enzyme functions best at temperature
(A) 30°C to 50°C
(B) 15°C to 25°C
(C) 20°C to 35°C
(D) 40°C to 50°C
Answer:
(C) 20°C to 35°C

Question 32.
As temperature changes from 30° to 45° C, the rate of enzyme activity will
(A) decrease
(B) increase
(C) first increase and then decrease
(D) first decrease and then increase
Answer:
(C) first increase and then decrease

Question 33.
Out of the following, which is not a property of enzymes?
(A) Specific in nature
(B) Proteinaceous
(C) Used up in reaction
(D) Increased rate of biochemical reaction
Answer:
(C) Used up in reaction

Question 34.
Majority of cellular enzymes function best at _______ PH.
(A) acidic
(B) basic
(C) neutral
(D) strong base
Answer:
(B) basic

Question 35.
The _______ action of enzyme with a substrate is explained by lock and key theory.
(A) relative
(B) specific
(C) random
(D) abstract
Answer:
(B) specific

Question 36.
Morphine, the first alkaloid isolated from ________
(A) Pisum sativum
(B) Hibiscus rosa sinensis
(C) Papaver somniferum
(D) Azadirachta indica
Answer:
(C) Papaver somniferum

Question 34.
Competitive Corner:

Question 1.
Prosthetic groups differ from co-enzymes in that –
(A) They can serve as co-factors in a number of enzyme – catalyzed reactions
(B) They require metal ions for their activity
(C) They (prosthetic groups) are tightly bound to apoenzymes
(D) Their association with apoenzymes is transient
Hint: Apoenzyme (protein part) and co-factor together form a complete catalytically active enzyme which is known as holoenzyme. The co-factors are of two types; metal ions and coenzymes. A coenzyme or metal ion that is very tightly or even covalently bound to the enzyme protein is known as a prosthetic group.
Answer:
(C) They (prosthetic groups) are tightly bound to apoenzymes

Question 2.
Consider the following statements:
1. Coenzyme or metal ion that is tightly bound to enzyme protein is called prosthetic group.
2. A complete catalytic active enzyme with its bound prosthetic group is called apoenzyme. Select the correct option.
(A) Both (i) and (ii) are false.
(B) (i) is false but (ii) is true.
(C) Both (i) and (ii) are true.
(D) (i) is true but (ii) is false.
Answer:
(D) (i) is true but (ii) is false.

Question 3.
Concanavalin A is:
(A) a lectin
(B) a pigment
(C) an alkaloid
(D) an essential oil
Answer:
(A) a lectin

Question 4.
Which one of the following carbohydrates is a heteropolysaccharide?
(A) Cellulose
(B) Starch
(C) Glycogen
(D) Hyaluronic acid
Answer:
(D) Hyaluronic acid

Question 5.
The two functional groups characteristic of sugars are
(A) Carbonyl and phosphate
(B) Carbonyl and methyl
(C) Hydroxyl and methyl
(D) Carbonyl and hydroxyl
Answer:
(D) Carbonyl and hydroxyl

Question 6.
Which one of the following statements is correct with reference to enzymes?
(A) Apoenzyme = Holoenzyme + coenzyme
(B) Holoenzyme = Apoenzyme + Coenzyme
(C) Coenzyme = Apoenzyme + Holoenzyme
(D) Holoenzyme = Coenzyme + Co-factor
Answer:
(B) Holoenzyme = Apoenzyme + Coenzyme

Question 7.
Which of the following are NOT polymeric?
(A) Nucleic acids
(B) Proteins
(C) Polysaccharides
(D) Lipids
Answer:
(D) Lipids

Balbharti Maharashtra State Board 11th Commerce Book Keeping & Accountancy Important Questions Chapter 3 Journal Important Questions and Answers.

Maharashtra State Board 11th Commerce BK Important Questions Chapter 3 Journal

1A. Answer in One Sentence:

Question 1.
What do you mean by Journalising?
Answer:
Journalisation means a process of recording two-fold effects of business transactions in the summarized form of debit and credit in the journal.

Question 2.
Which column in a journal is not filled in at the time of journalising?
Answer:
Ledger Folio column in a journal is not filled in at the time of journalising.

Question 3.
Which account is credited when Salary is paid by cheque?
Answer:
Bank Account is credited when salary is paid by cheque.

Question 4.
Why is a journal called the book of prime entry?
Answer:
Journal is called a book of prime entry because all the business transactions are recorded first in the journal in a chronological order i.e. in the order of their occurrence.

Question 5.
In which order the transactions are recorded in a journal.
Answer:
The transactions are recorded in a journal in chronological order i.e. in the order of their occurrence or taking place.

Question 6.
Which account is debited, when goods are destroyed by fire?
Answer:
When goods are destroyed by fire, the Loss by Fire Account is debited.

2. Correct the following statements and rewrite the statements.

Question 1.
Transactions can be recorded in any order in the Journal.
Answer:
Transactions must be recorded in chronological order in the Journal.

Question 2.
Trade discount is recorded in the books of accounts.
Answer:
A cash discount is recorded in the books of accounts.

Question 3.
Trade discount is calculated after cash discount while calculating discount on purchase or sales.
Answer:
Trade discount is calculated before cash discount while calculating discount on purchase or sales.

Question 4.
Trade discount is allowed for prompt payments.
Answer:
A cash discount is allowed for prompt payments.

Question 5.
The process of entering or recording the transactions in the Journal is called posting.
Answer:
The process of entering or recording the transaction in a Journal is called Journalising.

3. Do you agree or disagree with the following statements

Question 1.
Purchase of Assets should be debited to purchase A/c.
Answer:
Disagree

Question 2.
A cash discount is recorded in the books of Accounts.
Answer:
Agree

Question 3.
GST is imposed by the local body.
Answer:
Disagree

Question 4.
Capital is an asset for business organisations.
Answer:
Disagree

Question 5.
With NEFT, RTGS Transaction Cash A/c is affected.
Answer:
Disagree

Question 6.
On purchase of goods or assets output, GST A/c is credited.
Answer:
Disagree

Question 7.
5% GST Charge on luxury cars.
Answer:
Disagree

Question 8.
GST Generates income to Central Government only.
Answer:
Disagree

Question 9.
Ledger Folio column in Journal filled while passing Journal entry only.
Answer:
Disagree

Question 10.
Purchase of shares of TATA Ltd should be debited to TATA Ltd’s A/c.
Answer:
Disagree

Balbharti Maharashtra State Board 11th Commerce Book Keeping & Accountancy Important Questions Chapter 2 Meaning and Fundamentals of Double Entry Book-Keeping Important Questions and Answers.

Maharashtra State Board 11th Commerce BK Important Questions Chapter 2 Meaning and Fundamentals of Double Entry Book-Keeping

1. Answer in one sentence only.

Question 1.
State the meaning of the accounting equation.
Answer:
An equation that indicates or shows that the total assets of a business are always equal to the total liabilities of a business plus capital is called the accounting equation.

Question 2.
What do you mean by debt?
Answer:
To debit an account means to enter the entry or write on the left-hand side of an account.

Question 3.
Give two examples of personal accounts.
Answer:
Two examples of personal accounts are stated below:

1. Mr. Raghuvir Sharma’s Account
2. The Bank of India’s Account.

Question 4.
What is a Nominal Account?
Answer:
The account relating to business expenses, incomes, and gains is called a nominal account.
e.g. Rent A/c.

Question 5.
Give two examples of real accounts.
Answer:
Two examples of real accounts are:

1. Cash A/c
2. Goodwill A/c

Question 6.
State whether drawings increase or decrease owner’s equity.
Answer:
Drawings made by the owner of the business decrease its equity.

Question 7.
What is a conventional cash book?
Answer:
A cash book that is prepared to record not only cash transactions but all types of transactions such as credit purchase or sale, banking transactions, opening, and closing entries, adjustments entries is called a conventional cash book.

Question 8.
Explain the term dual aspect.
Answer:
Every transaction has two aspects i.e. for every debit there is corresponding and equal credit.

Question 9.
State the meaning of impersonal account.
Answer:
The account which is not of a person is called an impersonal account.

Question 10.
Write the rule of Real account.
Answer:
The rule of real account states that Debit what comes in and Credit what goes out.

Question 11.
Which account will be debited when goods are sold to Ram on credit?
Answer:
When goods are sold to Ram, Ram’s A/c will be debited.

Question 12.
Which account will be debited when Mr. Shyam has paid cash to you?
Answer:
Cash A/c will be debited when Mr. Shyam has paid cash to us.

2. Write one word/term or phrase which can substitute each of the following statements.

Question 1.
Expenses are paid before it is due.
Answer:
Prepaid Expenses

Question 2.
Income due but not yet received.
Answer:
Accrued Income

Question 3.
Carriage paid on the sale of goods.
Answer:
Carriage Outward

Question 4.
Statement of Assets & Liabilities.
Answer:
Balance Sheet

Question 5.
Account prepared to know Net Profit or Net Loss.
Answer:
Profit & Loss Account

Question 6.
Value of goods remaining unsold at the end of the year.
Answer:
Closing Stock

Question 7.
The provision was made to compensate the loss on account of likely debts.
Answer:
Provision for Bad & Doubtful Debts

Question 8.
The accounts are prepared at the end of the accounting year to know the profit or loss and financial position of the business.
Answer:
Final Accounts

Question 9.
An amount spent on promoting the sale of goods.
Answer:
Selling Expenses

Question 10.
Additional information is provided below the Trial Balance.
Answer:
Adjustments

3. Select the most appropriate alternatives from those given below and rewrite the statements.

Question 1.
___________ is excess of assets over liabilities.
(a) Goodwill
(b) Capital
(c) Investments
(d) Drawings
Answer:
(b) Capital

Question 2.
Discount earned is transferred to credit side of ___________ account.
(a) Current A/c
(b) Profit & Loss Account
(c) Trading
(d) Capital
Answer:
(b) Profit & Loss Account

Question 3.
___________ is a statement that shows the financial position of a business on a specific date.
(a) Trading account
(b) Trial Balance
(c) Profit & Loss A/c
(d) Balance Sheet
Answer:
(d) Balance Sheet

Question 4.
Outstanding expenses are shown on the ___________ side of Balance Sheet.
(a) Assets
(b) Liability
(c) Both
(d) None of these
Answer:
(b) Liability

Question 5.
Interest on Drawing is credited to ___________ Account.
(a) Trading
(b) Profit & Loss Account
(c) Capital
(d) All
Answer:
(b) Profit & Loss Account

Question 6.
Debit balance of Trading Account means ___________
(a) Gross Loss
(b) Net Loss
(c) Net Profit
(d) Gross Profit
Answer:
(a) Gross Loss

Question 7.
Carriage Inward is debited to ___________ Account.
(a) Trading A/c
(b) Profit & Loss
(c) Capital
(d) Bank
Answer:
(a) Trading A/c

Question 8.
Excess of credit over to debit in Profit & Loss Account indicates ___________
(a) Net Profit
(b) Gross Profit
(c) Gross Loss
(d) Net Loss
Answer:
(a) Net Profit

Question 9.
Closing stock is always valued at cost or market price which is ___________
(a) more
(b) less
(c) zero
(d) equal
Answer:
(b) less

Question 10.
When a specific date is not given, in that case, interest on the drawing is charged for ___________ month.
(a) Four
(b) Six
(c) Eight
(d) Nine
Answer:
(b) Six

4. Fill in the blanks.

Question 1.
Gross Profit is transferred to ___________ account.
Answer:
Profit & Loss Account

Question 2.
Debit Balance of Trading Account indicates ___________
Answer:
Gross Loss

Question 3.
Income Receivable appears on ___________ side of Balance Sheet.
Answer:
Asset

Question 4.
Interest on Bank Loan is debited to ___________ A/c.
Answer:
Profit & Loss Account

Question 5.
Profit and Loss Account is prepared to find out ___________ results of the business.
Answer:
Networking

Question 6.
All indirect/operating expenses are transferred to ___________ account.
Answer:
Profit and Loss Account

Question 7.
Interest of proprietor’s drawing is credited to ___________ account.
Answer:
Profit & Loss Account

Question 8.
An excess of debit over credit in the Profit & Loss A/c represents the ___________
Answer:
Net Loss

Question 9.
All direct expenses are transferred to ___________ account.
Answer:
Trading A/c

Question 10.
Balance Sheet is ___________ of assets & liabilities.
Answer:
Statement

5. Classify the following accounts under the types of Personal, Real, and Nominal accounts.

Question 1.
Investments A/c
Answer:
Real Account

Question 2.
Creditors A/c
Answer:
Personal Account

Question 3.
Land A/c
Answer:
Real Account

Question 4.
Purchase Returns A/c
Answer:
Personal Account

Question 5.
Cash A/c
Answer:
Real Account

Question 6.
Building A/c
Answer:
Real Account

Question 7.
Capital A/c
Answer:
Personal Account

Question 8.
Goodwill A/c
Answer:
Real Account

Question 9.
Interest received A/c
Answer:
Nominal Account

Question 10.
Depreciation A/c
Answer:
Nominal Account

Question 11.
Stationery A/c
Answer:
Nominal Account

Question 12.
Salary A/c
Answer:
Nominal Account

Question 13.
Excise duty A/c
Answer:
Nominal Account

Question 14.
Bank Loan A/c
Answer:
Personal Account

Question 15.
Bank Overdraft A/c
Answer:
Personal Account

Question 16.
Sales A/c
Answer:
Nominal Account

Question 17.
Return Inwards A/c
Answer:
Personal Account

Question 18.
Rent received A/c
Answer:
Nominal Account

Question 19.
Wages A/c
Answer:
Nominal Account

Question 20.
Discount received A/c
Answer:
Nominal Account

Question 21.
Debtors A/c
Answer:
Personal Account

Question 22.
Furniture & Fixtures A/c
Answer:
Nominal Account

Question 23.
Purchases A/c
Answer:
Nominal Account

Question 24.
Bad Debts A/c
Answer:
Nominal Account

Question 25.
Dadar Library A/c
Answer:
Personal Account

Question 26.
Rent paid A/c
Answer:
Nominal Account

Question 27.
Prepaid Insurance A/c
Answer:
Personal Account

Question 28.
Carriage Outwards A/c
Answer:
Nominal Account

Question 29.
Rent Receivable A/c
Answer:
Personal Account

Question 30.
Profit on sale of machinery A/c
Answer:
Nominal Account

Question 31.
Bills Payable A/c
Answer:
Personal Account

Question 32.
Bank of India A/c
Answer:
Personal Account

Question 33.
Carriage Inwards A/c
Answer:
Nominal Account

Question 34.
Stock A/c
Answer:
Real Account

Question 35.
Accrued Interest A/c
Answer:
Personal Account

Question 36.
Bank A/c
Answer:
Personal Account

Question 37.
12% Government Bonds A/c
Answer:
Real Account

Question 38.
Carriage A/c
Answer:
Nominal Account

Question 39.
Advertisement A/c
Answer:
Nominal Account

Question 40.
Conveyance A/c
Answer:
Nominal Account

Question 41.
Premises A/c
Answer:
Real Account

Question 42.
Octroi A/c
Answer:
Nominal Account

Question 43.
Postage A/c
Answer:
Nominal Account

Question 44.
Electricity Charges A/c
Answer:
Nominal Account

Balbharti Maharashtra State Board 11th Commerce Book Keeping & Accountancy Important Questions Chapter 1 Introduction to Book Keeping and Accountancy Important Questions and Answers.

Maharashtra State Board 11th Commerce BK Important Questions Chapter 1 Introduction to Book Keeping and Accountancy

1. Answer in One Sentence:

Question 1.
What is Transaction?
Answer:
The exchange of goods or services for money or money’s worth is called a transaction.

Question 2.
What is Cash Discount?
Answer:
The amount which is deducted by the seller from the amount due at the time of the receipt is called cash discount.

Question 3.
What is the entity concept?
Answer:
The business entity concept states that a business has a separate entity and has an independent legal existence distinct from the person who owns it.

Question 4.
What is the money measurement concept?
Answer:
The money measurement concept implies that every business transaction must be recorded in a common unit of measurement i.e. in terms of money only.

Question 5.
What is the consistency concept?
Answer:
The consistency concept implies that any policy adopted for accounting should be continuous or consistent throughout the business and it need not be changed generally unless and until circumstances demand.

Question 6.
What is conservatism?
Answer:
The concept of conservatism states that while deciding the policy of the enterprise the businessman has to anticipate no profit but provide for all possible losses.

Question 7.
What is accounting?
Answer:
Accounting is a process of recording, classifying, summarising, analyzing, and interpreting financial transactions and communicating the result thereof to the users of such information.

Question 8.
Name the financial statements prepared by a business.
Answer:
A businessman prepares the financial statements such as income statements i.e. Trading Account and Profit and Loss Account and Position Statement i.e. Balance Sheet.

Question 9.
Explain the term ‘Profit’.
Answer:
Excess of revenue income over revenue expenditure is termed as profit.

Question 10.
Explain the term ‘Cost Concept’.
Answer:
The concept according to which assets are recorded in the books of accounts at the price at which they are acquired or purchased is called the cost concept.

2. Give the word term or phrase which can substitute each of the following statements:

Question 1.
Dealings between two persons.
Answer:
Transaction

Question 2.
Business transaction in which cash is not paid or received immediately.
Answer:
Credit Transaction

Question 3.
An allowance is given by the receiver of the cash to the giver of cash at the time of payment.
Answer:
Cash Discount

Question 4.
Liability depends on the happening or not happening a certain event.
Answer:
Contingent Liability

Question 5.
Expenditure on fixed assets increases the earning capacity of the business.
Answer:
Capital Expenditure

Question 6.
System in which entry is recorded for cash as well as credit transactions.
Answer:
Accrual System

Question 7.
The concept under which comparison of one accounting period with the other period is possible.
Answer:
Consistency Concept

Question 8.
A science and art of correctly recording in the books of accounts, all those business transactions that result in the transfer of money or money’s worth.
Answer:
Bookkeeping

Question 9.
Exchange of goods and services either for cash or any other goods or services.
Answer:
Transaction

Question 10.
Sale or purchase of goods or services for immediate cash payment.
Answer:
Cash Transaction

Question 11.
Sale or purchase of goods or services for a certain value to be receivable or payable in the future.
Answer:
Credit Transaction

Question 12.
Commodity purchased or produced for sale.
Answer:
Goods

Question 13.
Excess of assets over liabilities.
Answer:
Capital

Question 14.
Excess of profit over normal profit.
Answer:
Super Profit

Question 15.
The total amount of goods and services are withdrawn by the proprietor for self-use.
Answer:
Drawings

Question 16.
Amount of discount deducted from the invoice price.
Answer:
Trade discount

Question 17.
The reputation of a business is expressed in terms of money.
Answer:
Goodwill

Question 18.
The concept states that assets when purchased should be recorded at cost price.
Answer:
Cost concept

Question 19.
The concept states that business operations will continue forever.
Answer:
Concept of Going Concern

Question 20.
A concept on which a double-entry bookkeeping system is based.
Answer:
Dual Aspect Concept

Question 21.
Rules of conduct are accepted universally to record business transactions.
Answer:
Accounting Principles

Question 22.
General ideas which convey certain meanings.
Answer:
Concepts

Question 23.
The general notion or abstract ideas on which accounting is based.
Answer:
Accounting Concept

Question 24.
The accounting concept suggests that a business has a separate identity from its owner.
Answer:
Business Entity Concept

Question 25.
The accounting concept states that monetary transactions are only recorded in the books of accounts.
Answer:
Money Measurement Concept

Question 26.
The money value for which assets are acquired or manufactured.
Answer:
Cost

Question 27.
Proprietor’s contribution to the business.
Answer:
Capital

Question 28.
Valuable things are owned by the business.
Answer:
Assets

Question 29.
Period of time for which accounts of the business are prepared.
Answer:
Financial year/Accounting year

Question 30.
Amount received after selling of goods or services.
Answer:
Revenue

Question 31.
Excess of revenue over its cost.
Answer:
Profit

Question 32.
Name the accounting concept on the basis of which the income statement is prepared.
Answer:
Accrual Accounting Concept

3. Select the most appropriate alternatives from those given below and rewrite the statements.

Question 1.
Money value of the reputation of business is known as ____________
(a) Copyright
(b) Goodwill
(c) Patents
(d) Trademark
Answer:
(b) Goodwill

Question 2.
Heavy advertising expenditure for launching a new product is called as ____________
(a) Capital expenditure
(b) Revenue Expenditure
(c) Deferred Revenue Expenditure
(d) None of these
Answer:
(c) Deferred Revenue Expenditure

Question 3.
Expenditure incurred on purchase of fixed asset is ____________
(a) Revenue Expenditure
(b) Capital Expenditure
(c) Deferred Revenue Expenditure
(d) None of these
Answer:
(b) Capital Expenditure

Question 4.
Concept which provides a line between present and future is known as ____________
(a) Going Concern Concept
(b) Cost Concept
(c) Accrual Concept
(d) Entity Concept
Answer:
(a) Going Concern Concept

Question 5.
Totalling of Journal or Ledger is called as ____________
(a) Posting
(b) Folio
(c) Casting
(d) Journalising
Answer:
(c) Casting

Question 6.
In cash transaction, goods or services are exchanged for ____________
(a) other goods
(b) other services
(c) immediate cash
(d) grains
Answer:
(c) immediate cash

Question 7.
The work of book-keeping is of ____________ nature.
(a) competitive
(b) primary/basic
(c) secondary
(d) none of these
Answer:
(b) primary/basic

Question 8.
Capital is ____________ of the business.
(a) asset
(b) liability
(c) property
(d) goodwill
Answer:
(b) liability

Question 9.
The work of accounting depends upon ____________
(a) book-keeping
(b) cash book
(c) subsidiary books
(d) ledger
Answer:
(a) book-keeping

Question 10.
____________ is the amount invested by the owner of a business.
(a) Cash
(b) Money
(c) Asset
(d) Capital
Answer:
(d) Capital

Question 11.
Revenue expenditure is ____________ in nature.
(a) capital
(b) outstanding
(c) recurring
(d) contingent
Answer:
(c) recurring

Question 12.
Amount withdrawn by the owner for his personal expenses is called ____________
(a) Drawings
(b) Personal expenses
(c) Cash
(d) Assets
Answer:
(a) Drawings

Question 13.
Financial statements are a part of ____________
(a) Book keeping
(b) Planning
(c) Accounting
(d) None of these
Answer:
(c) Accounting

Question 14.
A ____________ liability is an uncertain liability.
(a) Long term
(b) Contingent
(c) Current
(d) Fixed
Answer:
(b) Contingent

Question 15.
A Derson who is unable to nay his debts, is called ____________
(a) insolvent
(b) solvent
(c) well to do
(d) poor
Answer:
(a) insolvent

Question 16.
According to ____________ concept business shall go on for a long time.
(a) going concerned
(b) consistency
(c) materiality
(d) dual aspects
Answer:
(a) going concerned

Question 17.
According to ____________ concept, every business transaction has two aspects.
(a) going concerned
(b) materiality
(c) business entity
(d) dual aspects
Answer:
(d) dual aspects

Question 18.
According to ____________ concept revenue is recognised when it is earned.
(a) Realisation
(b) Accounting period
(c) Accrual
(d) Matching cost
Answer:
(c) Accrual

Question 19.
According to ____________ convention, while preparing planning anticipate losses.
(a) Materiality
(b) Consistency
(c) Conservatism
(d) disclosure
Answer:
(c) Conservatism

Question 20.
Customs and traditions which guide the accountants to prepare accounting statements are called ____________
(a) Conventions
(b) Principles
(c) Concepts
(d) Procedure
Answer:
(a) Conventions

Question 21.
According to ____________ concept, assets are recorded at a price paid to acquire them.
(a) Cost
(b) Money measurement
(c) Entity
(d) Dual aspect
Answer:
(a) Cost

4. State whether the following statements are true or false with reasons:

Question 1.
The trading concern is established for rendering services to society.
Answer:
This statement is False.
The main objective of trading concern is to earn profit. It is for traders’ livelihood, so the trading concern is not established for rendering services to the society.

Question 2.
Book-keeping is an art as well as a science.
Answer:
This statement is True.
Book-keeping is also considered as an art of recording business transactions because the writing of accounts in a specific style and format requires education, knowledge, training, skill, and experience. From another point of view, Book-keeping is a continuous process of collecting, analyzing, classifying, summarising, and recording the different types of business transactions. In brief, bookkeeping may be defined as “A science as well as an art of collecting, analyzing, classifying, summarising and recording all types of business transactions in a significant manner and in terms of money in a separate set of books.”

Question 3.
In Book-keeping & Accountancy non-monetary transactions are also recorded.
Answer:
This statement is False.
Only monetary transactions are recorded in Book-keeping & Accountancy. It is done to find financial results for the purpose of analyzing and interpreting.

Question 4.
Perpetual succession is explained by the concept of the entity.
Answer:
This statement is False.
The concept of entity is different from the perpetual succession. Entity means separate existence of business from the owner whereas perpetual succession means long life and continuation.

Question 5.
Accounting is useful only to the owner.
Answer:
This statement is False.
Accounting is not only useful for the owner but also to the suppliers, government, customers, lenders, etc.

Question 6.
Writing of account does not require specific skill and knowledge.
Answer:
This statement is False.
Writing of account requires specific skill and knowledge as book-keeping is an art and science of correctly recording business transactions.

Question 7.
The main objective of Bookkeeping is to keep permanent records of business transactions.
Answer:
This statement is True.
The record of business transactions is prepared for a specific period of time i.e. one year and it is preserved for a long period of time.

Question 8.
In credit transactions, goods or services are purchased for cash only.
Answer:
This statement is False.
In credit transactions, goods and services are purchased and sold for credit only. Credit means post-pone payments for a future date.

Question 9.
In barter transactions, goods or services are purchased for other goods or services.
Answer:
This statement is True.
Barter means exchange of goods or services for goods or services. No money is involved in barter transactions.

Question 10.
In cash transactions, goods or services are purchased for a certain value to be paid in the future.
Answer:
This statement is False.
In a cash transaction, goods or services are purchase or sold for spot payments or receipts. No credit is allowed.

Question 11.
Good is a commodity that is purchased for self-use.
Answer:
This statement is False.
Good is a commodity that is purchased for resale purposes. It is an article or a commodity in which businessman deals.

Question 12.
Amount due from other person is known as debt.
Answer:
This statement is True.
Debt is a total sum of money due from a person with whom the business has dealings. Accordingly, a person from whom such debt is due to a business is called the debtor.

Question 13.
Liabilities represent the debts or obligations that a business must receive in terms of money.
Answer:
This statement is False.
Liabilities refer to the total amount of obligations that a business has to pay in the future. Liability means the total amount owed by the business to other persons.

Question 14.
Capital = Liabilities – Assets.
Answer:
This statement is False.
Excess of business assets over business liabilities is called capital.
Capital = Assets – liabilities.

Question 15.
Drawings made by the businessman increase his capital.
Answer:
This statement is False.
Drawing means cash or goods withdrawn by the proprietor for his personal or family use. Drawings made by the businessman decreases his capital.

Question 16.
A person whose assets are equal to or greater than liabilities is known as insolvent.
Answer:
This statement is False.
Insolvent means a person whose liabilities are greater than assets is known as ‘Insolvent’.

Question 17.
A person whose assets are less than business liabilities is known as insolvent.
Answer:
This statement is True.
When a person is not able to pay liabilities is called insolvent. Liabilities are greater than assets.

Question 18.
The cost or sacrifice which is incurred to run the business is known as an income.
Answer:
This statement is False.
The cost or sacrifice which is incurred to run the business is known as an expenditure.

Question 19.
Benefits which are given by giver to the receiver is known as discount.
Answer:
This statement is False.
Discount is a concession given by the seller to the buyer. There are two types of discount,

• Cash discount
• Trade discount

Question 20.
Posting implies recording a transaction in a journal.
Answer:
This statement is False.
Posting means transferring or recording journal entries from the journal to the respective ledger accounts. Ledger is the main book of accounting.

Question 21.
Contingent liabilities can also be called doubtful liabilities.
Answer:
This statement is True.
The contingent liabilities are the liabilities whose occurrence depends upon the happening of a certain event that may or may not take place. So a contingent liabilities can also be called doubtful liabilities.

Question 22.
A sports club is a trading concern.
Answer:
This statement is False.
The sports club is a nontrading concern as they do not work for profit-making. They work for the promotion of sports.

Question 23.
A cash discount is an incentive allowed for the speedy recovery of income.
Answer:
This statement is True.
A cash discount is given by the creditor or seller to the debtor or buyer to induce him to make prompt payment. It is given at the time of cash payment.

Question 24.
Excess of revenue over expenses is called loss.
Answer:
This statement is False.
Excess of revenue over expenses is called profit. Your income is less and expenditures are less so you get profit.
Income ₹ 50,000 – Expenses ₹ 35,000 = Profit is ₹ 15,000.

Question 25.
Excess of liabilities over assets represents the solvency of a business.
Answer:
This statement is False.
Excess of liabilities over assets represents insolvency of business. A trader cannot pay his debts as liabilities are greater than his assets.
Liabilities ₹ 1,50,000 Assets ₹ 80,000.
₹ 1,50,000 – ₹ 80,000 = ₹ 70,000 deficiency.

Question 26.
A business can not run without bookkeeping.
Answer:
This statement is False.
Book-keeping is a recording of business financial transactions which is useful to prepare ledger, trial balance, financial statements. All the above are useful to take decisions, planning, liabilities, and assets so a businessman cannot run his business without book-keeping.

Question 27.
Bookkeeping is necessary only for organizing with profit objectives.
Answer:
This statement is False.
Books of accounts are maintained by trading and non-trading concerns. Non-trading concerns do not earn any profits so book-keeping is not necessary only with the objective of profit.

Question 28.
The figures of profit and net worth are disclosed by books of accounts.
Answer:
This statement is True.
The purpose of preparing books of accounts is to know financial details of organization from journal ledger, trial balance, final accounts proprietor to get an idea of his financial status. The purpose of financial books of accounts is to get profit and net worth etc.

Question 29.
Financial statements are an effective weapon in the hands of management.
Answer:
This statement is True.
With help of financial statements, management does planning, decision-making for the future. The past record gives ideas to the management to improve financial decisions like more profit better financial conditions etc. so financial statements are effective weapons in the hands of management.

Question 30.
Irregularities, frauds, and misappropriations can be detected only because of books accounts.
Answer:
This statement is False.
Irregularities frauds and misappropriations can be detected by auditing. Continuous and periodical auditing will detect the irregularities frauds and misappropriations which is done by a chartered accountant.

5. Do you agree or disagree with the following statements:

Question 1.
Goodwill is a tangible asset.
Answer:
Disagree

Question 2.
For income tax purposes an accounting year starts on 1st January and ends on 31st March.
Answer:
Disagree

Question 3.
Earning profits is an aim of Not for Profit Concern.
Answer:
Disagree

Question 4.
Trade discount is recorded in the books of accounts.
Answer:
Disagree

Question 5.
Wages paid on installation of machinery are revenue expenditures.
Answer:
Disagree

Question 6.
An amount that is not recoverable from debtors is called bad debt.
Answer:
Agree

Question 7.
The double-entry book-keeping system is invented in India.
Answer:
Disagree

Question 8.
Book-keeping does not have any rules and regulations for recording business transactions.
Answer:
Disagree

Question 9.
The owner of the business does not have any utility of book-keeping.
Answer:
Disagree

Question 10.
Bookkeeping cannot be used as financial evidence in a court of law.
Answer:
Disagree

Question 11.
It is not possible for management to plan and take decisions in business with help of book-keeping and accountancy.
Answer:
Disagree

Question 12.
Cash-withdrawn by the proprietor from his business for personal use is called capital.
Answer:
Disagree

Question 13.
A person who has to pay the business for getting goods and services on credit is known as the debtor.
Answer:
Agree

Question 14.
Trade discount is not recorded in the books of accounts.
Answer:
Agree

Question 15.
Purchase of goods is revenue expenditure.
Answer:
Agree

Question 16.
Heavy expenditure on advertising is deferred revenue expenditure.
Answer:
Agree

Question 17.
A solvent person’s assets are more than his liabilities.
Answer:
Agree

Question 18.
Net Worth = Total Assets – Outsiders Liabilities
Answer:
Agree

Question 19.
Conservatism’s concept means to play safe.
Answer:
Agree

Question 20.
The dual aspect means every transaction has two effects i.e. debit and credit.
Answer:
Agree

6. Complete the following sentences:

Question 1.
In barter transaction goods are exchange for ____________
Answer:
Goods

Question 2.
Asset is ____________ of the business.
Answer:
property

Question 3.
Capital expenditures are ____________ in nature.
Answer:
Non Recurring

Question 4.
A ____________ liability is an uncertain liability.
Answer:
Contingent

Question 5.
A person whose liabilities are more than his assets is known as ____________
Answer:
Insolvent

Question 6.
An article or a commodity which is purchase for resale in business is called ____________
Answer:
Goods

Question 7.
Customs and traditions which guide the accountants to prepare accounting systems are called ____________
Answer:
Conventions

Question 8.
Discount given by the creditor to the debtor on payment of cash is called ____________
Answer:
Cash discount

Question 9.
For tax purpose an year starts on 1st April and ends on 31st March is called ____________
Answer:
Accounting year

Question 10.
An institution which provides standard of accounting in India called ____________
Answer:
Institute of Chartered Accountants of India

Question 11.
Which accounting standard is followed for depreciation on fixed assets ____________
Answer:
AS-6

Question 12.
Brief explanation of an entry is called as ____________
Answer:
Narration

Question 13.
Businessman open ____________ type of bank account.
Answer:
Current

Question 14.
The main objective of business concern ____________
Answer:
making profits

Question 15.
Assets which are held in the business for a period of less than one year ____________
Answer:
Current Assets

Question 16.
10 years loan taken from bank by organisation is ____________ term loan.
Answer:
long

Question 17.
Heavy expenses paid on formation of an organisation is known as ____________ expenditure.
Answer:
Deferred Revenue

Question 18.
Dividend received on shares is ____________ income.
Answer:
Revenue

Question 19.
Loss on sale of old machine is ____________ loss.
Answer:
Capital