Biology

Cell Cycle and Chromosomes

1,219 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

Name the stage of cell cycle at which the following events occurs.

  1. Chromosomes are moved to spindle equator.
  2. Centromere splits and chromatids separate.
  3. Pairing between homologous chromosomes takes place.
  4. Crossing over between homologous chromosomes takes place.
    1. Anaphase, 2. Metaphase, 3. Zygotene, 4. Pachytene
    1. Anaphase, 2. Pachytene, 3. Zygotene, 4. Metaphase
    1. Metaphase, 2. Anaphase, 3. Zygotene, 4. Pachytene
    1. Anaphase, 2. Metaphase, 3. Pachytene, 4. Zygotene
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  1. Anaphase  -Chromosomes are moved to spindle equator.
    1. Metaphase -Centromere splits and chromatids separate.
    2. Zygotene -Pairing between homologous chromosomes takes place.
    3. Pachytene -Crossing over between homologous chromosomes takes place.
Multiple choice

Mitotic cell cycle is divided into 4 phases G1, S, G2 and M. Considering a mitotic cycle time of 18 hours, the distribution of period of time for each of these phases will be

  1. G1-1 S-3 G2-5 M-9

  2. G1-9 S-1 G2-3 M-5

  3. G1-9 S-5 G2-3 M-1

  4. G1-3 S-5 G2-9 M-1
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In an 18-hour mitotic cycle, G1 is typically the longest phase as the cell grows and prepares for DNA synthesis. G1 occupies ~50% (9 hours), S phase ~28% (5 hours) for DNA replication, G2 ~17% (3 hours) for preparation, and M phase ~5% (1 hour) for mitosis itself. This distribution reflects the biological priority of growth preparation.

Multiple choice

Directions: The following question consists of certain statements. You have to select the option representing the most logical sequencing of the given statements.

A. Chromosomes contain genes. B. Cells contain DNA. C. Chromosomes contain cells. D. Cells contain Chromosomes. E. Genes are present in cells. F. Genes are not present in cells.

  1. ACE

  2. ABC

  3. BCF

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

As chromosomes contain genes and cells contain chromosomes, therefore, genes are present in cells. Hence, option 4 is the answer.

Multiple choice

Barr body is found in the which of the following phases of the cell cycle?

  1. Interphase

  2. Intraphase

  3. GI phase

  4. Telophase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The interphase nuclei of female mammals differ from those of males in that a heterochromatic body is usually present on the inner face of the nuclear envelop in females. This structure, the sex chromatin or Barr body, protrudes from the surface of polymorphic nuclei (as a drumstick).

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.