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

Consider the following statements:

  1. Gregor Mendel is known as the 'Father of Genetics'.
  2. The total number of chromosomes in humans is 48.

Which of the given statements is/are incorrect?

  1. Only (1)

  2. Only (2)

  3. Both (1) and (2)

  4. Neither (1) nor (2)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(i) Statement (1) is correct. Gregor Mendel is known as the 'Father of Genetics'. (iii) Statement (2) is incorrect. The total number of chromosomes in humans is 46, out of which 44 are autosomes and two are sex determining chromosomes, i.e. X and Y.

Multiple choice

When a sperm with X chromosomes fertilizes the egg, the resulting zygote would develop into a child with

  1. XX chromosomes

  2. YY chromosomes

  3. XY chromosomes

  4. Any of the above options can be possible

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

Yes, it is correct. When a sperm with X chromosome fertilizes the egg, the resulting zygote would develop into a female child. When a sperm with Y chromosome fertilizes the egg, the resulting zygote would develop into a male child. A female has all the chromosomes as X.

Multiple choice

Somatic cells in human beings contain

  1. 46 pairs of chromosomes

  2. 23 pairs of chromosomes

  3. 26 chromosomes

  4. 23 chromosomes

  5. No chromosomes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The somatic cells in human beings have 23 pairs of chromosomes or 46 chromosomes

Multiple choice

Which of the following units is used to measure bacterial growth?

Bacterial growth is the division of one bacterium into two daughter cells in a process called binary fission.

  1. IU/L

  2. mM fraction

  3. O.D

  4. cfu/ml

  5. cell/colony
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

O.D, i. e., optical density. In spectroscopy, the absorbance, i.e., optical density of a material is a logarithmic ratio of the radiation falling upon a material to the radiation transmitted through a material. Measurements of absorbance are carried out in analytical chemistry. This measures the rate of growth of a bacterial culture.

Multiple choice

What causes the abnormal growth of the tumor in cancer?

  1. Abnormal mitotic division

  2. Accumulation of body fluid

  3. Abnormal meiotic division

  4. Metastasis

  5. Extra sensitivity to antigrowth signals
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Abnormal growth of the tumor results by abnormal tendency of mitosis in the tumor cells. These keep on dividing and results into tumor.

Multiple choice

44 + X in a person shows which syndrome?

  1. Patau's syndrome

  2. Turner's syndrome

  3. Edward's syndrome

  4. Down's syndrome

  5. Klinfelter's syndrome
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

It is a chromosomal abnormality in which all or part of one of the X chromosome is absent.

Multiple choice

Which of the following statements is incorrect?

  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 like bacteria that lack a well-defined nuclear region are called prokaryotes.

Multiple choice

Select the correct statement regarding mitosis in humans.

  1. All body cells undergo the process of mitosis continously from the date of conceiving till death.

  2. Every body cell going through the process of mitosis divides into two complete new cells that are usually identical to the cell from which they formed.

  3. It takes about three days for a cell to complete all six phases of mitosis.

  4. Through mitosis, body produces new sex cells.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Both the original and the new cells normally are identical in their components and functions. This assures that replacement cells in skin and other body tissues are faithful copies.

Multiple choice

Which of the following statements about superficial cleavage is correct?

Cleavage is the process of rapid, successive mitotic division of zygote into large cells within a period extending from fertilization to blastula or beginning of gastrulation. All divisions in cleavage are mitotic in nature with the rate of cleavage depending on species & temperature. Early cleavage is synchronous but a late cleavage of the cell division is asynchronous.

  1. It is the cleavage is restricted in active cytoplasm of animal pole.

  2. It occurs in micro or isolecithal eggs resulting blastomere are approximately of equal size.

  3. The cleavage remains restricted to the periphery cytoplasmic region.

  4. It is the process of rapid, successive mitotic division of zygote into large cells.

  5. The cleavage produces unequal size blastomere including micromeres and macromere due to polarization of yolk holoblastic.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In centrolecithal eggs the cleavage remains restricted to the periphery cytoplasmic region,  which is called superficial cleavage. E.g, Arthropods, mainly insects.

Multiple choice

What is unequal holoblastic cleavage?

Cleavage is the process of rapid, successive mitotic division of zygote into large cells within a period extending from fertilization to blastula or beginning of gastrulation. All divisions in cleavage are mitotic in nature with the rate of cleavage depending on species & temperature. Early cleavage is synchronous but a late cleavage of the cell division is asynchronous.

  1. It is the cleavage remains restricted to the periphery cytoplasmic region.

  2. It is the process of rapid, successive mitotic division of zygote into large cells.

  3. It is the type of cleavage, which is restricted in active cytoplasm of animal pole.

  4. It is the type of cleavage in mesolecithal and telolecithal eggs.

  5. It occurs into micro or isolecithal eggs resulting blastomere are approximately of equal size.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In mesolecithal and telolecithal eggs due to polarization of yolk holoblastic cleavage produces unequal size blastomere including micromeres [small size blastomere] and macromere [large size] is called unequal holoblastic cleavage. E.g, lower fishes and amphibians.

Multiple choice

A cell cultured in colchicines undergoes a complete cell cycle, except for the fact that chromosomes donot migrate to the poles during anaphase. What can be concluded from this?

  1. Colchicines do not affect the microtubules.

  2. DNA replication does not necessarily results in the chromosome separation.

  3. Centromere represent under replicated DNA.

  4. Spindle is made after interphase.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Colchicine inhibits microtubule polymerization, preventing spindle fiber formation during mitosis. Since chromosomes cannot attach to spindle fibers, they fail to separate and migrate to opposite poles during anaphase. DNA replication occurs normally in S phase, but chromosome segregation cannot complete without functional microtubules.

Multiple choice

When the nucleus of a red blood cell present in a frog, which does not replicates DNA, is transplanted into an enucleated frog egg, the egg goes through several cell divisions. Which of the following is the best interpretation for this phenomenon?

  1. Isolated red blood cell nuclei synthesises DNA.

  2. Nucleus plays no role in cell division.

  3. Enucleated frog egg can divide.

  4. Cytoplasm controls nuclear DNA replication.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When a differentiated nucleus (from red blood cell that doesn't normally replicate DNA) is transplanted into an enucleated egg, the egg's cytoplasm reprograms the nucleus. The cytoplasm contains factors that can reactivate dormant genes and initiate DNA replication and cell division, demonstrating that cytoplasmic factors control nuclear activity.