Question

Explain : [4 MARKS]
1) G1 phase
2) S phase or Synthesis phase
3) G2 phase

Answer 1

1) 1 Mark
2) 1 Mark
3) 2 Marks

1) G1 phase is the preparatory stage for the upcoming division. The cell grows in size besides synthesizing RNA and proteins. No change occurs in its DNA content.

2) During this phase, new DNA is synthesized as per the old DNA template. Thus each chromosome now consists of two chromatids joined at the centromere.

3) In the third phase (stage) of cell cycle, cell growth and synthesis of RNA and protein continues. It must again be re-emphasised that during G2 phase, the amount of DNA present in the cell is double of what was present in the beginning of the interphase, but the paired diploid condition is still maintained.