AP BIOLOGY

Detailed explanation-1: -A gene variant is a permanent change in the DNA sequence that makes up a gene. This type of genetic change used to be known as a gene mutation, but because changes in DNA do not always cause disease, it is thought that gene variant is a more accurate term.

Detailed explanation-2: -Mutation is a process that causes a permanent change in a DNA sequence. Changes to a gene’s DNA sequence, called mutations, can change the amino acid sequence of the protein it codes for-but they don’t always. A point mutation is a change to single DNA letter.

Detailed explanation-3: -DNA mutations never go away and can be passed down to other cells and even offspring. Mutations in RNA, however, are only temporary because RNA is quickly degraded after it is used by the cell. RNA polymerase is more prone to error than DNA polymerase and has less repair mechanisms.

Detailed explanation-4: -When Replication Errors Become Mutations. Incorrectly paired nucleotides that still remain following mismatch repair become permanent mutations after the next cell division. This is because once such mistakes are established, the cell no longer recognizes them as errors.