Chromosomes

Chromosomes are thread-like structures made up of DNA and histone proteins. They are found inside the nucleus of eukaryotic cells and are responsible for the storage, expression and transfer of genetic information from one generation to the next. During cell division, chromatin condenses to form visible chromosomes, ensuring proper distribution of genetic material.

Structure of Chromosomes

Each chromosome consists of two identical sister chromatids joined at a point called the centromere. These chromatids carry the same genetic information. Chromosomes ensure the equal distribution of genetic material during cell division and maintain hereditary continuity.

Types of Chromosomes

There are two major bases for the classification of chromosomes:

1. Based on Centromere Position

This classification depends on where the centromere is located along the length of the chromosome.
  1. Metacentric: Centromere is exactly in the middle, forming two equal arms.
  2. Submetacentric: Centromere is slightly off-center, producing one short and one long arm.
  3. Acrocentric: Centromere is close to one end, making one very short and one very long arm.
  4. Telocentric: Centromere is at the end of the chromosome, appearing to have only one arm (not found in humans).
Based on Centromere Position This classification depends on where the centromere is located along the length of the chromosome. Metacentric: Centromere is exactly in the middle, forming two equal arms. Submetacentric: Centromere is slightly off-center, producing one short and one long arm. Acrocentric: Centromere is close to one end, making one very short and one very long arm. Telocentric: Centromere is at the end of the chromosome, appearing to have only one arm (not found in humans).

2. Based on Role in Sex Determination

This classification is based on whether the chromosome determines the sex of an individual or not.
  1. Autosomes: These chromosomes control general body characteristics. Humans have 22 pairs of autosomes.
  2. Sex Chromosomes (Allosomes): These determine the sex of the individual. In humans, females have XX and males have XY sex chromosomes.






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