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

Meiosis occurs in

  1. germ cells

  2. somatic cells

  3. guard cells

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Correct option is (1).

Multiple choice

Sub divisions in cell cycle (in the correct sequence) are

  1. S, G2, M and G1

  2. G1, S, G2 and M

  3. S, M, G1 and G2

  4. G2, G1, M and S
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is the sequence of events in cell cycle. The cell cycle or cell-division cycle is the series of events that take place in a cell leading to its division and duplication of its DNA (DNA replication) to produce two daughter cells.

Multiple choice

Structure of nuclear membrane helps in

  1. organisation of spindle

  2. synapsis of homologus chromosomes

  3. nucleocytoplasmic exchange of material

  4. anaphasic separation of daughter chromosome
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Nuclear membrane separates cytoplasm from nucleus. Thus, it helps in the exchange of materials between the two.

Multiple choice

Chiasmata are most appropriately observed in meiosis during

  1. diakinesis

  2. diplotene

  3. metaphase II

  4. pachytene

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

Diplotene is a point at which paired chromosomes remain in contact during the first metaphase of meiosis (diplotene). At this point, crossing over and exchange of genetic material occurs between the strands.

Multiple choice

Down syndrome is caused due to which of the following?

  1. Increase in number of chromosomes in 21st pair autosome

  2. Decrease in number of chromosomes in 21st pair autosome

  3. Increase in number of chromosomes in 18th pair autosome

  4. Decrease in number of chromosomes in 18th pair autosome
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Down syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is typically associated with physical growth delays, characteristic facial features and mild to moderate intellectual disability.

Multiple choice

Colour blindness is due to

  1. recessive female chromosome

  2. dominant female chromosome

  3. recessive male chromosome

  4. dominant male chromosome
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The gene which is responsible for the condition is carried on the X chromosome. Due to this, more men are affected than women.

Multiple choice

Barr body is associated with

  1. sex chromosome of female

  2. sex chromosome of male

  3. autosome of female

  4. autosome of male
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

It is a small and densely staining structure in the cell nuclei of females that consists of a condensed and inactive X chromosome. It is regarded as diagnostic of genetic femaleness.

Multiple choice

Alleles are

  1. alternate forms of genes

  2. sex chromosomes

  3. homologus chromosomes

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Each of the two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome is called an allele.

Multiple choice

During mitosis, the number of chromosomes

  1. changes

  2. does not change

  3. may change if cell is mature

  4. may change if cell is immature

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

There is no change in the number of chromosomes in mitosis. Therefore, it is called as equivalent division.

Multiple choice

L-shaped chromosomes are also called as

  1. acrocentric

  2. telocentric

  3. sub-metacentric

  4. None of these

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

It is a chromosome with the centromere so placed that it divides the chromosome into two arms of strikingly unequal length. Thus, it forms the L-shape.