Question

Compare and contrast the chromosome structure of viruses, bacteria, and eukaryotes.

Answer 1

Structure of Chromosomes of Viruses :-

1) Viruses contain either DNA or RNA as their genetic material.

2) The nucleic acid may be either single stranded or double stranded.

3) The viral chromosome is enclosed within a protein shell called capsid.

4) The viral chromosome and its protein coat together are called nucleocapsid.

5) Number of genes in viral genome may vary from 3 to hundreds.

Structure of chromosome of Bacteria :-

1) Bacteria contain their chromosome as circular,double stranded DNA molecule.

2) The entire genome is a single circle,but often extra circles are present called plasmid.

3) Bacterial cell contains only one chromosome.

4) Bacterial chromosome is naked.No associated protein is present.

Structure of chromosome of Eukaryotes :-

1) Eukaryotic chromosomes are linear chromosomes and much larger than prokarytotic chromosome.

2) It contains a linear DNA molecule.

3) It is associated with histone protein.

4) In eukaryoteic chromosome plasmid is absent.

5) In a eukaryotic cell two or more different chromosomes may be present.

6) Eukaryotic chromosomes are also stored in the nucleus of the cell unlike prokaryotes.