Question

When the centromere is situated in the middle of two equal arms of chromosomes, the chromosome is referred as :

• A. Metacentric
• B. Telocentric
• C. Sub-metacentric
• D. Acrocentric

Answer 1

The correct option is A Metacentric

Chromosomes are condensed DNA that are visible only in dividing cells. They essentially have a primary constriction known as the centromere which hold the two sister chromatids of a chromosome together.
Based on the position of the centromere, the chromosomes can be classified into the following four types:

1. Metacentric chromosome:
Centromere lies in the middle forming two equal arms of the chromosome.

2. Sub-metacentric chromosome:
Centromere is present slightly away from the middle of the chromosome resulting in one shorter arm and one longer arm.

3. Acrocentric chromosome:
The centromere is situated close to the end of the chromosome forming one extremely short and one very long arm.

4. Telocentric chromosome:
Centromere is terminal.


Fig: Types of chromosomes based on the position of centromere