Question

A cell has undergone DNA replication and the number of chromosomes has doubled.what will happen next?

Answer 1

Answer:

The correct answer is A. The cell will synthesize all the proteins it needs to divide in two.

Explanation:

DNA replication takes place in the S phase of the cell cycle which results in doubling of chromosomes. After synthesis phase cell enters the G2 phase in which the cell prepares itself to move into the mitotic phase to divide.

G2 phase nearly lasts for 3-4 hours and cells in this phase continues to grow in size and produce essential proteins which is required in mitosis for the division of a cell into two daughter cells.

It has also a checkpoint called G2 checkpoint which confirms that the cell is ready to move into the mitotic phase or not. Therefore, the right answer is A.  

Answer 2

Answer:

A. The cell will synthesize all the proteins it needs to divide in two.

Explanation:

Sequence of phases of cell cycle:

Interphase (G1-->S--->G2) -----> M phase (prophase--->metaphase--->anaphase--->telophase).

DNA replication and duplication of chromosomes occur during S phase of cell cycle. It is followed by G2 phase which is marked by synthesis of proteins needed for M phase and continuous cell growth. Initiation of spindle formation and movement of centriole to opposite poles are the events of prophase that follows G2 phase. Metaphase is the next phase which includes alignment of chromosomes at the cell equator.