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Cell Division

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Number of Questions: 15
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Tags: 20 Chromosomes Cell: Structure and Function Cell & Cell division Meiosis Cell Division
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Name the stage at which progressive condensation and coiling of chromatin fibres take place:

  1. Late Prophase or early Metaphase

  2. Leptotene

  3. Pachytene

  4. Zygotene

  5. Anaphase


Correct Option: B
Explanation:

It is the stage at which progressive condensation and coiling of chromatin fibres take place.

Volume of nucleus is increased and chromosomes develop a number of major coils, which grow in size as prophase proceeds. This phenomenon takes place in____________.

  1. zygotene

  2. pachytene

  3. leptotene

  4. diplotene

  5. diakinesis


Correct Option: C
Explanation:

Volume of nucleus is increased and chromosomes develop a number of major coils, which grow in size as prophase proceeds. This phenomenon occurs in Leptotene.

In which stage the chromosome number is reduced to half, with each set moving towards opposite poles?

  1. Second meiotic division

  2. Prophase I

  3. Telophase I

  4. Metaphase I

  5. Anaphase I


Correct Option: E
Explanation:

In Anaphase I  the chromosome number is reduced to half,  with moves towards one pole and the remaining half to the other pole.

Which of the following statement is not correct with respect to the chromosomes?

  1. Chromosomes are straight, rod-like, coiled or thread-like in structure.

  2. Chromosomes range from 0.5 to 30 microns in length and from 0.2 to 3 microns in diameter.

  3. Each Chromosome has a centromere, which holds together the two chromatids.

  4. There is a variable number of chromosomes in each cell.

  5. There are two types of chromosomes found in the human body - Autosomes and Allosomes.


Correct Option: D
Explanation:

This statement is incorrect. There is a fixed number of chromosomes in each cell.

Duplicated chromosomes are joined at a point termed

  1. centrosome

  2. centromere

  3. centriole

  4. chromatid

  5. chromomere


Correct Option: B
Explanation:

The centromere is the part of a chromosome that links sister chromatids. During mitosis, spindle fibres attach to the centromere via the kinetochore. Centromeres were first defined as genetic loci that direct the behavior of chromosomes.

Duplication of DNA occurs in

  1. G1 phase

  2. G2 phase

  3. S phase

  4. M phase

  5. Prophase


Correct Option: C
Explanation:

S-phase (synthesis phase) is the part of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase. Precise and accurate DNA replication is necessary to prevent genetic abnormalities, which often lead to cell death or disease.

In meiotic cell division, four daughter cells are produced by two successive divisions in which

  1. first division is equational and second is reductional

  2. first division is reductional and second division is equational

  3. both divisions are reductional

  4. both divisions are equational

  5. there is no division at all


Correct Option: B
Explanation:

First division is reductional and second division is equational in meiotic cell division.

The nuclear membrane and nucleolus become indistinguishable during____________.

  1. Telophase

  2. Metaphase

  3. Prophase

  4. Interphase

  5. Anaphase


Correct Option: B
Explanation:

Metaphase is a stage of mitosis in the eukaryotic cell cycle in which condensed and highly coiled chromosomes, carrying genetic information, align in the middle of the cell before being separated into each of the two daughter cells. Metaphase accounts for approximately 4% of the cell cycle's duration.

The centromere divides into two in

  1. Prophase

  2. Telophase

  3. Anaphase

  4. Metaphase

  5. Interphase


Correct Option: D
Explanation:

Metaphase is a stage of mitosis in the eukaryotic cell cycle in which condensed and highly coiled chromosomes, carrying genetic information, align in the middle of the cell before being separated into each of the two daughter cells. Metaphase accounts for approximately 4% of the cell cycle's duration. In this stage only the centromere divides into two.

Which of the following statement is false?

  1. Meiosis leads to recombination of character.

  2. Chromosomes other than sex-chromosomes are autosomes.

  3. Asexual reproduction is accomplished through mitosis.

  4. Chromosomes are thickest and shortest in telophase.

  5. Cytokineses takes place through furrow in animal cells.


Correct Option: D
Explanation:

This statement is false. Chromosomes are thickest and shortest in anaphase.

How many chromosomes are found in a cell of human?

  1. 20 pairs

  2. 23 chromosomes

  3. 46 chromosomes

  4. 46 pairs

  5. 20 chromosomes


Correct Option: C
Explanation:

46, i.e., 23 pairs of chromosomes are present in the human cell.

The disappearance of spindle and uncoiling of chromosomes takes place in ________.

  1. anaphase

  2. telophase

  3. pachytene

  4. metaphase

  5. prophase


Correct Option: B
Explanation:

Telophase is the final stage in both meiosis and mitosis in a eukaryotic cell. During telophase, the effects of prophase and prometaphase (the nuclear membrane and nucleolus disintegrating) are reversed. Two daughter nucleiform in each daughter cell, and phosphatases de-phosphorylate the nuclear lamins at the ends of the cell, forming nuclear envelopes around each nucleus.

Which of the following is not correct with respect to meiosis?

  1. It involves two successive divisions resulting in the formation of four daughter nuclei.

  2. Prophase is of longer duration and complex.

  3. Number of chromosomes in daughter cells is half to that of the mother cells.

  4. It occurs in somatic cells and equational division takes place.

  5. Meiosis forms gametes and spores and maintains the chromosome number constant from generation to generation.


Correct Option: D
Explanation:

This statement is not true. It occurs in generative cells and reductional division takes place.

Mitosis is very significant. Which of the following is not a significance of Mitosis?

  1. It helps to maintain linear heredity of an organism by keeping the chromosome numbers constant in daughter cells.

  2. It helps in development of organism from zygotic stage to adult stage.

  3. It is the means of repair and regeneration of cells and replacement of the old and dead cells.

  4. Sexual reproduction is accomplished only through mitosis.

  5. Details of mitosis are similar in all organisms, which emphasizes the unity of life.


Correct Option: D
Explanation:

This statement is false. Asexual reproduction is accomplished only through mitosis.

The period between two successive mitotic divisions is

  1. diakinesis

  2. mitosis

  3. anaphase

  4. diplotene

  5. interphase


Correct Option: E
Explanation:

Interphase is the phase of the cell cycle in which the cell spends the majority of its time and performs the majority of its purposes including preparation for cell division. This is the period between two successive mitotic divisions.

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