bio312 chapter15

Mutation

A change in the DNA sequence that can lead to alterations in gene function or expression.

Xeroderma pigmentosum (XP)

An autosomal recessive disease characterized by sensitivity to sunlight and development of precancerous skin growths due to faulty DNA repair mechanisms.

Spontaneous mutations

Mutations that occur naturally, often due to errors in DNA replication or spontaneous lesions.

Induced mutations

Mutations that occur due to external factors like environmental agents or chemicals known as mutagens.

Base substitution

A type of point mutation where one base pair is replaced by another.

Transition mutation

A point mutation that replaces a base with another base of the same chemical category (purine to purine or pyrimidine to pyrimidine).

Transversion mutation

A point mutation that replaces a base with a base of a different chemical category (purine to pyrimidine or vice versa).

Synonymous mutation

A mutation that does not change the amino acid sequence of a protein.

Nonsynonymous mutation

A mutation that changes the amino acid sequence of a protein.

Frameshift mutation

A mutation caused by the addition or removal of bases that shifts the reading frame of the gene.

DNA repair mechanisms

Cellular processes that correct damaged DNA to maintain genomic integrity.

Ames Test

A biological assay used to evaluate the mutagenic potential of compounds by measuring mutation rates in bacterial systems.

Oncogenes

Mutated genes that, when activated, promote cell growth and division, contributing to cancer development.

Tumor-suppressor genes

Genes that normally inhibit cell proliferation or promote apoptosis; mutations lead to loss of function and can contribute to cancer.

Photodimers

Covalently bonded pairs of pyrimidine bases in DNA resulting from UV light exposure, causing distortions in the DNA structure.

Base excision repair (BER)

A repair process that corrects damage to individual nitrogenous bases.

Nucleotide excision repair (NER)

A repair process that removes a short single strand of damaged DNA, allowing for repair synthesis.

Translesion synthesis

A DNA damage tolerance process that allows the DNA replication machinery to replicate past a site of DNA damage.

Malaria resistance and the Duffy antigen

A genetic mutation that provides individuals protection against malaria by altering receptor sites on red blood cells.