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

Which of the following statements regarding mitosis is INCORRECT?

  1. Mitosis occurs in all eukaryotic and prokayotic cells.

  2. The process of mitosis is fast and highly complex.

  3. Mitosis produces two daughter cells.

  4. Mitosis begins when the chromosomes condense and become visible.

  5. As mitosis completes, the cell begins cytokinesis.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mitosis occurs only in eukaryotic cells and the process varies in different groups. For example, animals undergo an "open" mitosis, where the nuclear envelope breaks down before the chromosomes separate while fungi, such as Aspergillus nidulans and Saccharomyces cerevisiae (yeast) undergo a "closed" mitosis, where chromosomes divide within an intact cell nucleus.

Multiple choice

Which of the following can be excluded from the category of the functions of mitosis?

  1. Development and growth

  2. Cell replacement

  3. Regeneration

  4. Asexual reproduction

  5. An adaptation to deal with stress.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Abundant evidence indicates that facultative sexual protists tend to undergo sexual reproduction under stressful conditions. For instance, the budding yeast Saccharomyces cerevisiae switches to meiosis (sexual reproduction) under starvation conditions.This proves that in protists and simple multicellular eukaryotes, meiosis is an adaptation to deal with stress.

Multiple choice

The nucleoli and the nuclear envelope gets dissappeared in

  1. anaphase II

  2. metaphase II

  3. prophase II

  4. telophase II

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

In prophase II  one can observe the disappearance of the nucleoli and the nuclear envelope again as well as the shortening and thickening of the chromatids. Centrioles move to the polar regions and arrange spindle fibres for the second meiotic division.

Multiple choice

Cytokinesis is the physical process of cell division, which divides the cytoplasm of a parental cell into two daughter cells. Which of the following statements regarding the cytokinesis is FALSE?

  1. It begins shortly after the onset of sister chromatid separation.

  2. A contractile ring, made of muscle myosin II and actin filaments assembles parallelly at the cell cortex.

  3. The process of abscission physically cleaves this midbody into two.

  4. Abscission depends on septin filaments.

  5. The position at which the contractile ring assembles is dictated by the mitotic spindle.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A contractile ring, made of non-muscle myosin II and actin filaments, assembles equatorially (in the middle of the cell) at the cell cortex (adjacent to the cell membrane). Myosin II uses the free energy released when ATP is hydrolysed to move along these actin filaments, constricting the cell membrane to form a cleavage furrow.

Multiple choice

A women with 47 chromosomes due to three copies of chromosome 21 is characterized by

  1. Turner syndrome

  2. Down syndrome

  3. Superfemaleness

  4. Triploidy
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

 Down syndrome is a chromosomal abnormality characterized by the presence of an extra copy of genetic material on the 21st chromosome, either in whole (trisomy 21) or part (such as due to translocations). The effects of the extra copy varies greatly from individual to individual, depending on the extent of the extra copy, genetic background, environmental factors, and random chance.

Multiple choice

Centromere is required for

  1. movement of chromosomes toward poles

  2. cytoplasmic cleavage

  3. crossing over

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

  Centromeres appear as a constriction. They have a role in the separation of chromosomes into daughter cells during cell division (mitosis and meiosis).So,centromere is required for movement of chromosomes toward poles 

Multiple choice

The salivary gland chromosomes in the diptera larvae, are useful in gene mapping because

  1. they have endoreduplicated chromosomes

  2. these are fused.

  3. these are easy to stain.

  4. these are much longer in size.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  Polytene Chromosomes (Salivary Chromosomes) were discovered by Balbiani (1881) in the salivary glands of Chironomus tantans. Later they were found in salivary glands of many insect larvae including Drosophila. Polytene chromosomes are formed by somatic pairing of homologous chromosomes followed by their repeated replication or endomitosis. They are in permanent prophase.

Multiple choice

Which of the following statements is/are incorrect?

  1. A diagram depicting chromosomes of haploid set of an organism ordered in a series of decreasing size is known as idiogram.
  2. In case of inversion when the inverted segment of chromosome includes centromere, it is known as paracentric inversion.
  3. Transmission of a gene from male parent to female child to male grand child is known as criss-cross inheritance.

  1. Only 1

  2. Only 2

  3. Only 3

  4. 1 and 2

  5. 2 and 3
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In case of inversion when the inverted segment of chromosome includes centromere, it is known as pericentric inversion.

Multiple choice

By which of the following term can the functional segments of DNA be defined

  1. Genes

  2. Chromosomes

  3. Chromatin

  4. Chromatids

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Genes are specific, functional segments of DNA that code for particular proteins or traits. Chromosomes are structures containing DNA and proteins, chromatin is the complex of DNA and proteins, and chromatids are duplicated chromosome copies. Only genes represent functional DNA segments.

Multiple choice

A couple gone for counseling following first trimester miscarriages. As part of their evaluation, both the parents had chromosomal analysis. The father is found to have the karyotype 46, XY, inv8(p13q23). What interpretation is drawn?

  1. This is a normal variant, likely of no significance.

  2. This is an abnormal chromosome that would cause congenital anomalies if transmitted to the developing foetus.

  3. This rearrangement might cause chromosomal imbalance in developing foetus and could explain multiple miscarriages.

  4. This rearrangement might cause dicentric or acentric chromosomes in developing foetus, which would probably not be compatible with survival of the developing foetus.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is a pericentric inversion. Crossing over within the inversion loop would lead to duplication and deficiency of parts of chromosome 8, which might cause congenital anomalies.

Multiple choice

Which of the following statements is not true?

  1. Functional segments of DNA are called genes.

  2. Chromatin material is organised to form chromosomes during cell division.

  3. Chromosomes are composed of DNA and proteins.

  4. Organisms lacking nuclear membrane are called eukaryotes.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Organisms lacking nuclear membrane are called prokaryotes.