Question

A chromosome having subterminal centromere is
a. Acrocentric
b. Sub-metacentric
c. Telocentric
d. Metacentric

Answer 1

Hint: In a genome, each chromosome is morphologically identified on the basis of the position of its centromere. The centromere can be located on any part of a chromosome. It divides the chromosome into two arms which may be equal or unequal.

Complete answer:
A chromosome is threadlike nuclear material which has a special constitution, individuality and function. E. Strasburger in 1875 first demonstrated their presence in the eukaryotic cell.
W. Waldeyer in 1888 gave these nuclear bodies the term chromosomes.

Chromosomes can be classified depending on the position of the centromere.
> When the centromere is present right in the centre of the chromosome, it is called metacentric chromosome. In this, both the arms of the chromosome are of equal length. Metacentric chromosomes look V-shaped during anaphase.

> When the centromere is located on one side of the centre or is sub-median, it is called sub-metacentric chromosome. These appear L-shaped in anaphase.

> When a centromere is located far from the centre and towards the terminal end of the chromosome, it is called acrocentric chromosome. This results in one very long and one very short arm. Acrocentric chromosomes appear J-shaped during anaphase.

> When the centromere is found at the very end of the chromosome, it is called telocentric chromosome. This condition is however, very rare.

So from the above explanation we can say that,The correct answer is option (A).

Note: The location of centromere on the chromosome is controlled by a part of chromosomal DNA termed centromeric DNA. A segment of a chromosome that lacks a centromere is called an acentric fragment.