Question

Which of the following best describes the DNA content and the number of chromosomes at the end of S and M phases of the cell cycle in mitosis, if the DNA content of the cell in the beginning of cell cycle ($G1$ phase) is considered as C and the number of chromosomes $2N$?

• A. $2C$ and $2N$ for S phase; $2C$ and $2N$ for M phase
• B. $2C$ and N for S phase; $2C$ and N for M phase
• C. $2C$ and $2N$ for S phase; C and $2N$ for M phase
• D. C and N for S phase; C and $2N$ for M phase

Answer 1

The correct option is C $2C$ and $2N$ for S phase; C and $2N$ for M phase

C. 2C and 2N for S phase; C and 2N for M phase

Solution: In the S phase the DNA content gets doubled as the event of replication occurs at this phase but the number of chromosome remains unchanged.

In M phase, the increased amount of DNA gets equally divided into the two daughter cells but the number of chromosome remains unchanged.

So the correct answer is "2C and 2N for S phase; C and 2N for M phase"