Question

Assertion: Aneuploidy may be of hypoploidy or hyperdiploid type.
Reason: Monosomy lacks one pair of chromosomes.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
C. The assertion is correct but Reason is incorrect.
D. Both Assertion and Reason are incorrect.

Answer 1

Aneuploidy and Monosomy are genetic terms used to give information regarding the number of chromosomes present in a cell. These conditions give rise to several genetic disorders.

Complete answer: Aneuploidy is the condition that arises when the number of chromosomes that should be ideally present in a cell (23 pairs = 46 chromosomes), is either less or more.
As the name suggests, hypoploidy is the condition wherein the number of chromosomes is less than 46, and hyperdiploid is the condition where the number of chromosomes is more than 46.
So, the assertion stands to be correct.

Ideally, in any diploid organism, every chromosome must be present in a pair but in the case due to any faults in cell division, if any chromosome is present alone, then this condition is what we call monosomy.
So, monosomy is characterized by the absence of a single chromosome, and not a pair of chromosomes.
This implies that the Reason is false.

So, the correct answer is option C. Assertion is correct but Reason is incorrect.

Note: Aneuploidy leads to genetic disorders such as Turner’s syndrome which occurs due to the 21st trisomy and the Klinefelter’s syndrome which occurs due to the presence of an extra Y chromosome (22+ XYY).