Mutations and Mutagenic Agents

Flashcards about mutations, mutagenic agents, and related concepts based on lecture notes.

What are mutagens?

Environmental agents that alter DNA and cause mutations.

What is mutagenesis?

The process of inducing a mutation.

What are induced mutations?

Mutations that arise as a result of an environmental agent such as a chemical or radiation.

What are chemical mutagens?

Chemicals that cause mutations if cells are exposed to them at high frequencies or for prolonged periods.

What are naturally occurring mutagens?

Mutagenic agents that are present at normal levels within natural environments and may cause mutations.

What are biological mutagens?

Viruses, bacteria, fungi and their products.

What are Non-biological mutagens?

Metals (mercury, cadmium) that naturally occur in the environment.

What are physical mutagens?

Include heat and ionising radiation.

What is ionizing radiation?

A harmful type of radiation that has enough energy to break chemical bonds in molecules, including DNA.

What is mutation?

A collective term for a change in DNA.

What are spontaneous mutations?

Arise randomly as a result of an error in a natural process such as DNA replication in cells.

What are point mutations?

Changes to a single base pair of DNA and affect only a single gene.

What are chromosomal mutations?

Move whole blocks of genes to different parts of a chromosome or to another chromosome entirely.

What are frameshift mutations?

Occur when one or more nucleotides are inserted or deleted, causing a shift in the reading frame of the genetic code.

What is the heritability of mutations dependent on?

The possibility that a mutation will be passed down through generations depends on whether the mutation occurs in a non-reproductive (somatic) cell or a reproductive (germline) cell.

What are silent mutations?

Changes in the DNA sequence that do not cause a change in amino acid because of the redundancy of the genetic code, and therefore have no effect on proteins.

What are neutral mutations?

Changes in DNA that result in an amino acid of the same type as the original where the change does not significantly affect the structure of the protein

What is a chromosomal deletion?

Occurs when a section of DNA is removed and not replaced.

What is a chromosomal insertion (duplication)?

Occurs when a portion of DNA is duplicated (or doubled) and inserted.

What is a chromosomal inversion?

Occurs when a section of DNA is removed, turned around through 180 degrees, and then reinserted into the chromosome.

What is chromosomal translocation?

Occurs when a section of DNA is moved from one chromosome to a non-homologous chromosome.

What is Aneuploidy?

Occurs when one or more extra copies of an entire chromosome are made or an entire chromosome is missing, leading to an abnormal number of chromosomes in the cell.

What is a somatic mutation?

Mutation in a non-reproductive body cell that may lead to a localised effect, such as the development of a tumour in a part of the organism, but it will not be passed on to the next generation.

What is a germline mutation?

Mutation in a reproductive cell where the mutation will be passed on to every cell in the offspring of the gamete

What is junk DNA?

Parts of non-coding DNA that seemed to have neither a protein-coding nor a regulatory function

What are transposable elements?

Inserted DNA elements.

What is the bottleneck effect?

genetic drift occurring as a result of a natural disaster.

What is the founder effect?

genetic drift occurring due to a few individuals in a population (founding individuals) becoming geographically isolated from the original population

What is gene flow?

changes allele frequency due to the mixing of new individuals in a population