Question

A cell has a diploid or 2N chromosome number of 26 in its somatic cells. How many chromatids would you expect to see in G2?

Answer 1

In the cycle, Cell passes through Interphase and mitotic phase.

Interphase consists of G_1, S, G₂ phase.

G₁ phase is characterised by pre replication of DNA. Here, the cell is active and increases in size but does not replicates DNA. Here the chromosome has one chromatid.

S phase is the synthesis phase of cell cycle where replication of DNA occurs. The DNA content of cell is doubled but the number of chromosomes of remains same. The number of chromatid becomes 2 after this phase.

G₂ phase is post DNA replication phase of cell cycle. It acts as the checkpoint to decide whether the cell is ready o enter the mitotic cycle. Besides, proteins are secretd and cell grows to enter in the mitotic cycle during G₂ phase.

So, when the diploid number of chromosome is 26, then, number of chromatids will be 26x2= 52, but the chromosome number will remain same as 26.