A point mutation is a mutation that only affects a single nucleotide of the nucleic acid. Point mutations most commonly involve the substitution of one base for another (which changes the complementary base as well in DNA). The term point mutationt also includes insertions or deletions of a single base pair.
Types of point mutation -
(I)frameshift mutation- When there is an insertion or deletion of one or more bases. In other words, bases gets added or removed.
(II) Silent mutation- This is when a point mutation occurs, but it doesn't change the organism. It may be a mutation that doesn't occur on a gene so the codons aren't affected, or it may code for a similar amino acid that still functions correctly.
(III) Nonsense mutation- In this a codon is altered in such a way that it leads to a premature stop before the protein is done. There are a few codons that indicate the amino acids can stop being added and the protein is done