Question

The number of bivalents is 8 in prophase I. What is the number of chromosomes during anaphase II?

• A. $4$
• B. $8$
• C. $16$
• D. $32$

Answer 1

Answer: (A)

$4$

In prophase I homologous chromosome get attached (synapse) along with their lengths and exchange DNA. They are called bivalents or tetrads. In anaphase I, there is separation of the chromosomes towards the poles without breaking at the centromeres. During anaphase II, the sister chromatids of each chromosome separate and move towards the opposite poles. Each chromatid is called daughter chromosome. The number of chromosomes in anaphase II will be halved.

Thus, the correct answer is option A.