Question

The shorter and longer arms of a submetacentric chromosome are referred to as

• A. q-arm and p-arm respectively
• B. m-arm and n-arm respectively
• C. s-arm and 1-arm respectively
• D. p-arm and q-arm respectively

Answer 1

The Correct Option is D

The sub-metacentric chromosome has the centromere closer to one end, resulting in one arm that is shorter (p) and one arm that is longer (q).

Submetacentric chromosomes do not have the centromere directly in the middle. The cell's centre and the centromere are not exactly in the same spot. As a result, neither component is symmetrical or of equal length. For instance, human chromosomes 4 to 12 are submetacentric.

The tight, crowded area in a chromosome known as the centromere. Heterochromatin is a container for repeated DNA sequences with a high degree of specialization, such as satellite DNA. The centromere functions as the location for kinetochore assembly, making it crucial for chromosomal alignment at the metaphase plate and subsequent chromosome segregation during cellular division. The chromosomal arms are identified based on the presence of the centromere. The arm that is comparatively shorter is known as p, while the longer arm is known as q. The chromosome can be classified as metacentric, sub metacentric, acrocentric, telocentric, sub telocentric, or holocentric depending on where the centromere is located.

A chromosome with its centromere close to the centre is said to be sub metacentric. As a result, the chromosomal arms (i.e., the p and q arms) have slightly different lengths and might perhaps take the form of an L. Metacentric chromosomes are defined as having equal numbers of chromosomal arms.

These chromosomes are sub metacentric in humans: chromosome 2, chromosome 4, chromosome 5, chromosome 6, chromosome 7, chromosome 8, chromosome 9, chromosome 10, chromosome 11, chromosome 12, chromosome 17, chromosome 18, and the X chromosome.