Mutations and Cancer

These flashcards cover key terms and concepts related to mutations and cancer, providing definitions to aid in understanding the material.

Mutation

A change in the genetic material of a cell or virus.

Mutagen

Physical or chemical agents that can cause mutations.

Carcinogen

A chemical that can cause cancer and is often mutagenic.

Point Mutation

A change in a single nucleotide pair of a gene.

Base Substitution

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

Silent Mutation

A mutation that does not alter the amino acid sequence.

Missense Mutation

A mutation that changes a single amino acid in a polypeptide.

Nonsense Mutation

A mutation that converts a normal codon into a stop codon.

Frameshift Mutation

Mutations caused by insertions or deletions of nucleotides, altering the reading frame.

Proto-Oncogene

A normal gene that, when altered, can become an oncogene that promotes uncontrolled cell growth.

Oncogene

A mutated gene that contributes to the conversion of a normal cell into a cancerous cell.

Tumor-Suppressor Gene

A gene that encodes a protein responsible for regulating cell growth and preventing cancer.

p53

A tumor suppressor gene that plays a crucial role in preventing cancer by regulating the cell cycle and apoptosis.

Germ-line Mutation

A mutation that occurs in gametes and can be passed to offspring.

Somatic Mutation

A mutation that occurs in non-germline cells and cannot be inherited.

DNA Repair

Mechanisms of cellular repair that correct DNA damage to minimize mutations.

Induced Mutation

Mutations that are caused by environmental factors or mutagens.

Spontaneous Mutation

Mutations that occur without external influence, often due to normal biological processes.

Cell Cycle

The series of phases that a cell goes through to divide and replicate.

Cancer

A group of diseases characterized by uncontrolled cell division and growth.

Tumor

An overgrowth of cells that can be benign or malignant.

Radiation damage: Ionizing radiation

x-ray, gamma rays = high energy; penetrates deeply to create free radicals

Nonionizing radiation

UV rays: has less energy: only penetrates surface can cause thymine dimers

Direct repair

a repair enzyme recognizes incorrect DNA structure directly converts it back

nucleotide excision repair

portion of DNA strain containing abnormal nucleotide is removed and replaces

Mismatch repair

a base pair mismatch is detected, and a strand surrounding DNA is removed and replaces

how proto-oncogenes can be changed: missense mutation

chemical mutagens… can lead to cancer

how proto-oncogenes can be changed: gene amplification

increase in a copy = too much protein

how proto-oncogenes can be changed: chromosomal translocation

2 chromosomes break; switch ends’ specific translocations can lead to cancer

Proto-Oncogene: Ras protein

promotes ell division through cellular signal transduction using GTP. intercellular protein that hydrolyses GTP

Tumor suppressor genes: p53

tumor suppressor gene that acts as DNA damage sensor, can activate DNA repair proteins and apoptosis (about 50% of people have cancer associated with this defect gene)

carcinogens

about 80% of all human cancers are related to exposure to exposers of __________ (agents that increase the likelyhood of developing cancer)

what carcinogens are likely togive you cancer?

UV light and cigarette smoke (are mutagens that promote genetic changes in somatic cells)

how many cells can cancer originate from?

ONE (cell and its its offspring grows abnormally)