Question : Show composition, structure and type of chromosomes.

1.	Question : Show composition, structure and type of chromosomes.
Answer» Solution :Chromatin contains DNA and some basic proteins called HISTONES, some non histone proteins and also RNA. A single human cell has approximately two metra long THREAD of DNA distributed among its forty six chromosomes. (23 pairs) Every chromosome essentially has a primary CONSTRICTION or the centromere on the sides of which disc shaped structures called kinetochores are present. Based on the position of the centromere, the chromosomes can be classified into FOUR types : Metacentric : The metacentric chromosome has middle centromere forming two equal arms of the chromosome. Sub-metacentric : The sub-metacentric chromosome has centromere slightly away from the middle of the chromosome resulting into one shorter arm and one longer arm. Acrocentric : In case of acrocentric chromosome the centromere is situated CLOSE to its end forming one extremely short and one very long arm. Telocentric : Telocentric chromosome has a terminal centromere.

Discussion