Question

A somatic cell that has just completed the S phase of its cell cycle, as compared to gamete of the same species, has-

• A. four times the number of chromosomes and twice the amount of DNA
• B. twice the number of chromosomes and four times the amount of DNA
• C. the same number of chromosomes but twice the amount of DNA
• D. twice the number of chromosomes and twice the amount of DNA

Answer 1

The correct option is B

twice the number of chromosomes and four times the amount of DNA

The correct answer is B.

The explanation for the correct answer:

1. A somatic cell is a cell with two complete sets of chromosomes (2n).
2. Somatic cells are present everywhere in the body.
3. However, gametes possess a single set of chromosomes (n).
4. Gametic cells are restricted to reproductive organs.
5. In the S phase, "S" stands for synthesis.
6. In this stage, DNA is synthesized or replicated.
7. The chromosome number remains the same in the S phase of cell division.
8. This is because in the S phase, DNA is replicated in the cell nucleus (quantity of DNA is increased).
9. Whereas, in a somatic cell that has completed the S phase, chromosome number will double and the amount of DNA present in the gametic cell will become four times.

Final answer: A somatic cell that has just completed the S phase of its cell cycle, as compared to a gamete of the same species, has twice the number of chromosomes and four times the amount of DNA