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

Mitotic cell cycle is categorised usually into 4 phases- G1, S, G2 and M. Considering mitotic cycle time of 18 hours, distribution of time period (in hours) for every phase 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
D Correct answer
Explanation

In mitotic cell division, a cell that previously replicated each of its chromosomes isolates the chromosome in its nuclei into 2 similar chromosome sets where each set in its own nucleus. Distribution of time period (in hours) for every phase will be 3, 5, 9 and 1.

Multiple choice

Cell division is, where a parent cell is divided into 2 or more daughter cells. Typically, cell division occurs as part of larger cell cycle. In eukaryotes, it is of 2 types: vegetative (daughter cell is similar to parent cell) & reductive (chromosome number in daughter cell is decreased by half for producing haploid gametes) cell division. Prokaryotes also possess vegetative cell division termed as binary fission.

The mitosis promoting factor (MPF) that propels the animal cell into division stage has 2 important sun units: 1 is catalytic & other is regulatory. Which of following is regulatory sub unit of MPF?

  1. Ubiquitin

  2. Cyclin

  3. Cdk (Cyclin dependent kinase)

  4. Proline
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The mitosis promoting factor (MPF) that propels the animal cell into division stage has 2 important sun units: 1 is catalytic & other is regulatory. Cdk (Cyclin dependent kinase) is a protein kinase family which regulates cell cycle. It also regulates transcription, processing of mRNA & differentiation of nerve cells.  

Multiple choice

Cell division is where a parent cell is divided into 2 or more daughter cells. Typically cell division occurs as part of larger cell cycle. In eukaryotes, it is of 2 types: vegetative (daughter cell is similar to parent cell) & reductive (chromosome number in daughter cell is decreased by half for producing haploid gametes) cell division. Prokaryotes also possess vegetative cell division termed as binary fission.

Colchine arrests either mitotically dividing cell at metaphase by__________.

  1. dislodging chromosomes from fibrous elements of spindle and consequently the chromosome remain confined to equatorial plane

  2. preventing movement of spindle fibers as the result of which chromosomes fail to go to opposite poles

  3. preventing polymerisation of tubulin into microtubules of spindle

  4. destroying contractile property of spindle protein which ultimately coagulates
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Colchine arrests either mitotically dividing cell at metaphase by preventing polymerisation of tubulin into microtubules of spindle.

Multiple choice

Which of the following characterises the sexual development of the fetus?

  1. The sex of the developing embryo is determined by a single gene present on the Y chromosome.

  2. In the absence of a Y chromosome, the sexual development of the developing embryo will fail to follow any pattern.

  3. The maturation of the fetal gonads into the female type are initiated in the presence of estrogens.

  4. The sex of the developing embryo is determined by the set of genes on the Y chromosome.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A single gene on the Y, called SRY, triggers testes development in the early embryo and once these begin to form, the rest of the embryo also becomes male. Thus, the sex of the developing embryo is determined by a single gene present on the Y chromosome.

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

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.