Mutation, DNA Repair, and Cancer

This set of flashcards covers key terms and concepts related to mutations, DNA repair mechanisms, and the relationship between mutations and cancer as outlined in the lecture.

Mutation

A heritable change in the genetic material essential to the continuity of life, serving as a source of variation for natural selection.

Consequences of Mutations

Mutations can be harmful or beneficial, with most new mutations likely to be harmful.

DNA Repair Systems

Mechanisms that reverse DNA damage to maintain genetic integrity.

Point Mutation

A relatively small change in the sequence of bases in a particular gene, which may result in silent, missense, or nonsense mutations.

Silent Mutation

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

Missense Mutation

A mutation that changes one amino acid in a polypeptide, which may or may not alter protein function.

Nonsense Mutation

A mutation that changes a normal codon into a stop codon, leading to a truncated protein.

Frameshift Mutation

A mutation caused by the addition or deletion of nucleotides that alters the reading frame of the gene.

Natural Selection

The process by which certain traits become more or less common in future generations based on their effects on survival and reproduction.

Carcinogen

An agent that increases the probability of developing cancer, often by causing mutations in DNA.

Oncogene

A mutated gene that has the potential to cause cancer by promoting uncontrolled cell growth.

Tumor-Suppressor Gene

A gene that normally protects a cell from one step on the path to cancer; mutations can lead to loss of this function and contribute to cancer development.

Ames Test

A test that uses bacteria to assess the mutagenic potential of chemical compounds.

Nucleotide Excision Repair (NER)

A DNA repair mechanism that removes a segment of DNA containing an abnormal nucleotide and replaces it using the complementary strand as a template.

p53 Gene

A tumor-suppressor gene that regulates the cell cycle, DNA repair, and apoptosis; defects in this gene are common in cancers.

Rb Protein

A tumor-suppressor protein that inhibits the cell cycle progression from G1 to S phase by binding to and inhibiting the transcription factor E2F.

Metastasis

The spread of cancer cells from the original site to other parts of the body, a key feature in malignant tumors.

Genetic Mosaic

A condition resulting from somatic mutations that lead to patches of mutant tissue within an organism.

Induced Mutations

Mutations caused by external environmental factors, such as radiation or chemicals.

Spontaneous Mutations

Mutations that arise naturally from biological processes, often at a low rate.

Chemotherapy

A cancer treatment that uses chemical substances to kill rapidly dividing cells, including cancer cells.

Immunotherapy

A type of cancer treatment that uses the body’s immune system to fight cancer.

Proto-oncogene

A normal gene that can become an oncogene due to mutations or increased expression.