Question

Explain the types of chromosomes.

Answer 1

Types of chromosomes can be easily identified during cell division.

1. Metacentric: The centromere is exactly at the mid-point in this chromosome, and therefore the chromosome looks like the English letter ‘V’. The arms of this chromosome are equal in length.
   
2. Sub-metacentric: The centromere is somewhere near the mid-point in this chromosome which therefore looks like English letter ‘L’. One arm is slightly shorter than the other.
   
3. Acrocentric: The centromere is near one end of this chromosome which therefore looks like the English letter ‘j’. One arm is much smaller than other.
   
4. Telocentric: The centromere is right at the end of this chromosome making the chromosome look like the English letter ‘i’. This chromosome consists of only one arm.
   

Generally, in somatic cells chromosomes are in pairs. If the pair consists of similar chromosomes by shape and organization, they are called ‘homologous chromosomes’ and if they are not similar they are called ‘heterologous chromosomes’. In case of organisms that reproduce sexually one of the chromosomal pairs is different from all than others. Chromosomes of this different pair are called ‘sex chromosomes’ or allosomes and all other chromosomes are called ‘autosomes’.