Question

What is point mutation? Give one example.

Answer 1

Mutation refers to the alternation in the sequence of nucleotides of the genome of an organism. Mutation occurs from the errors that occur during DNA replication, meiosis or mitosis or any type of damage to the DNA. Mutation results in insertion or deletion of segments of DNA due to mobile genetic elements.

Complete answer:
A point mutation is a type of mutation where a single nucleotide base is changed from a DNA or RNA sequence from the genome of an organism. In this type of mutation all other nucleotides remain unchanged but only one nucleotide gets deleted, inserted or changed. Point mutation mostly occurs during DNA replication as stranded DNA molecules create two single strands of DNA each of which is a template for production of a complementary strand. A single point mutation changes the whole DNA sequence and rate of mutation may increase by mutagens.
There are multiple reasons which lead to occurrence of point mutation which are ultraviolet light and higher frequency light which is capable of ionizing electrons which affects DNA. Reactive oxygen molecules with free radicals which can harm the DNA molecule which leads to both single stranded DNA breaks and double stranded DNA breaks. DNA bonds can also degrade which also lead to mutation.

Note: Point mutation may have a severe effect on reproduction and behavior of a protein which depends on the location where the mutation occurs in the amino acid sequence of the protein. This minute change in the DNA sequence can lead to change in the entire structure which can lead to change in function of the molecule.