Question

What are the 4 types of chromosomes?

Answer 1

Chromosomes:

1. A chromosome is a DNA molecule that consists of a part or all of the genetic material of an organism.
2. The chromosome is present in the nucleus of each cell, and it is packaged into thread-like structures.
3. Structurally, each chromosome is composed of DNA that is tightly coiled around special proteins called histones.

4 types of chromosomes are:

Sub metacentric chromosomes:

1. These are chromosomes whose centromere is present near the middle and divides the chromosome into two unequal arms.
2. It is an L-shaped chromosome.
3. Most chromosomes in humans are submetacentric, e.g. 2^nd, 4^th to 12^th, 17^th, 18^th, and X chromosomes.

Acrocentric chromosomes:

1. These are chromosomes whose centromere is present near the end of chromosomes.
2. It forms a very short p arm and a very long q arm.
3. E.g. 13th, 14th, 15th, 21st, 22nd, and Y chromosomes are acrocentric in humans.

Telocentric chromosomes:

1. These are chromosomes that have centromeres present at the end of the chromosome.
2. It is not observed in humans.
3. The shorter p arm is barely visible.
4. The shape of the chromosome at the anaphase is like the letter ‘i’.

Metacentric chromosomes:

1. These are chromosomes whose centromere separates the chromosome into two equally sized arms and is located in the center of each one.
2. The metacentric chromosome is shaped like an X.
3. E.g. 1^st, 3^rd, 16^th, 19^th, and 20^th are metacentric chromosomes in humans.