Question

What are the two main types of mutations?

Answer 1

Mutations:

1. They are the changes in the DNA sequence of an organism.
2. The change in the DNA sequence of an organism occurs due to exposure to mutagens ( chemicals that cause mutation )and viral infection.

Two types of mutation :

Point Mutation: The mutations that usually occur due to the change in a single base pair by substitution. In this type of mutation, a single base pair such as adenosine is substituted by another base pair such as guanosine.

Point mutations are of three types:

1. Silent mutation – In this mutation the mutated codon codes for the same amino acid, changes the sequence of the peptide chain of protein
2. Missense mutation – In this mutation the mutated codon codes for a different amino acid, changes the sequence of the peptide chain of protein
3. Nonsense mutation – In this, the mutated codon is the stop codon, which causes the shortening of the peptide chain of the protein.

Frame-shift Mutation:

1. There is a change in the reading frame of codons due to the deletion or insertion of nucleotides.
2. It changes the codon of mRNA which leads to a change in the peptide chain of the protein.