Biology

Cell Cycle and Chromosomes

1,348 Questions

Explore a curated list of questions covering the cell cycle, mitosis, and meiosis. Topics include DNA replication, chromosomal structures, and genetic disorders. This material is essential for students preparing for biology and general science competitive exams.

Cell cycle eventsDNA replicationMeiosis processChromosomal structuresGenetic disorders

Cell Cycle and Chromosomes Questions

Multiple choice

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.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

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

Multiple choice

Duplicated chromosomes are joined at a point termed

  1. centrosome

  2. centromere

  3. centriole

  4. chromatid

  5. chromomere
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

Multiple choice

Duplication of DNA occurs in

  1. G1 phase

  2. G2 phase

  3. S phase

  4. M phase

  5. Prophase
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

Multiple choice

The nuclear membrane and nucleolus become indistinguishable during____________.

  1. Telophase

  2. Metaphase

  3. Prophase

  4. Interphase

  5. Anaphase
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

Multiple choice

The centromere divides into two in

  1. Prophase

  2. Telophase

  3. Anaphase

  4. Metaphase

  5. Interphase
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

Multiple choice

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.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

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

Multiple choice

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

  1. anaphase

  2. telophase

  3. pachytene

  4. metaphase

  5. prophase
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

Multiple choice

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.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

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

Multiple choice

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.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

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

Multiple choice

The period between two successive mitotic divisions is

  1. diakinesis

  2. mitosis

  3. anaphase

  4. diplotene

  5. interphase
Reveal answer Fill a bubble to check yourself
E Correct answer
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.