types of chromosomes
Answers
types of chromosomes
A. Autosomes and Sex Chromosomes
1)Human chromosomes are of two types autosomes and sex chromosomes.
2)Genetic traits that are linked to the sex of the person are passed on through the sex chromosomes. 3)The rest of the genetic information is present in the autosomes.
4)Humans have 23 pairs of chromosomes in their cells, of which 22 pairs are autosomes and one pair 5)of sex chromosomes, making a total of 46 chromosomes in each cell.
B. On the Basis of Number of Centromeres
1)Monocentric with one centromere.
2)Dicentric with two centromeres.
3)Polycentric with more than two centromeres
4)Acentric without centromere. Such chromosomes represent freshly broken segments of 5)chromosomes which do not survive for long.
6)Diffused or non-located with indistinct centromere diffused throughout the length of chromosome.
C. On the Basis of Location of Centromere
1)Telocentric are rod-shaped chromosomes with centromere occupying the terminal position, so that the chromosome has just one arm.
2)Acrocentric are also rod-shaped chromosomes with centromere occupying a sub-terminal position. One arm is very long and the other is very short.
3)Sub-metacentric chromosomes are with centromere slightly away from the mid-point so that the two arms are unequal.
4)Metacentric are V-shaped chromosomes in which centromere lies in the middle of chromosome so that the two arms are almost equal.