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What is mean by chromosome? Explain its types.

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  • The structure in the nucleus of cells which carries hereditary characteristics is called as chromosome which is mainly made up of nucleic acids and proteins.
  • It is made up of DNA appearing dumbbell shaped midway during the cell division.
  • There are four types of chromosomes which are classified on the basis of position of their centromeres.

The following are the types of chromosomes.

1) metacentric chromosome:

  • In metacentric chromosome the centromere is situated at the middle so that two equal arms will be formed and hence the chromosome looks like English letter V as shown in figure below.

2) sub – metacentric chromosome:

  • In sub-metacentric chromosome the centromere is situated slightly apart from the exact middle position so that two arms will be formed out of which one is longer than the other and hence it looks like the English letter L as shown in figure below.

3) Acrocentric chromosome:

  • In Acrocentric chromosome the centromere is situated at the one end of the chromosome due to which one arm formed will be very longer and the other arm will be very shorter and hence it looks like a English letter j as shown in figure below.

4) Telocentric chromosome:

In Telocentric chromosome the centromere is located at the one of the terminal end so that the chromosome has only one arm and hence looks like English letter i as shown in figure below.

 

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