Question

In human males all the chromosomes are paired perfectly except one. This/these unpaired chromosomes is/are:

1. large chromosome
2. small chromosome
3. Y chromosome
4. X chromosome

Options

• (i) and (ii)

• (iii) only

• (iii) and (iv)

• (ii) and (iv)

Answer 1

(iii) and (iv)

Explanation:

In human males, there are 23 pairs of chromosomes. Of these, 22 pairs are autosomes and are perfectly matched in size and shape. The 23rd pair consists of the X and Y chromosomes. Since the X chromosome is large and the Y chromosome is much smaller, they are not perfectly paired.

Therefore, the unpaired chromosomes are the X and Y chromosomes.