Gene Mutation and Molecular Medicine

These flashcards cover key concepts related to gene mutation, types of mutations, and their effects on phenotypes and disease.

Mutation

A change in the nucleotide sequence of DNA that can be passed from one cell or organism to another.

Induced Mutation

Mutations caused by environmental factors, such as chemicals and radiation, that alter DNA structure.

Mutation Hot Spots

Regions in DNA where bases are more susceptible to mutation.

Silent Mutation

A mutation that usually does not affect protein function and may occur in a non-coding region or code for the same amino acid.

Loss of Function Mutation

A mutation where the gene may not be expressed at all or the protein does not function; nearly always recessive.

Gain of Function Mutation

A mutation that leads to a protein with altered function, usually dominant, and commonly found in cancer.

Conditional Mutation

A mutation that alters the phenotype only under certain restrictive conditions.

Reversion Mutation

A mutation that can reverse the effects of a previous mutation, returning the DNA to its original sequence.

Point Mutation

A change in a single nucleotide that can result in a gain, loss, or substitution of that nucleotide.

Transition Mutation

A substitution of one purine for another purine, or one pyrimidine for another pyrimidine.

Transversion Mutation

A substitution of a purine for a pyrimidine or vice versa.

Missense Mutation

A mutation that results in the substitution of one amino acid for another in a protein.

Nonsense Mutation

A base substitution that results in a stop codon in the mRNA, leading to a truncated, usually nonfunctional protein.

Frame-shift Mutation

A mutation caused by insertions or deletions of bases that alter the reading frame during translation.

Promoter Mutation

A mutation that alters the rate of transcription of a gene.

Chromosomal Mutation

Extensive changes in DNA often caused by breakage and rejoining of DNA molecules.

Deletions

Chromosomal mutations where a part of DNA is lost during replication.

Duplications

Chromosomal mutations where a segment of DNA is copied, leading to an extra segment.

Inversions

Chromosomal mutations where a segment of DNA breaks and reattaches in the opposite orientation.

Translocations

Chromosomal mutations where a segment of DNA breaks off and attaches to another chromosome.

Spontaneous Mutation

Mutations that occur with no outside influence and are permanent.

Chemical Mutagen

An agent that can cause mutations by altering bases in DNA.

Ionizing Radiation

A type of radiation that creates free radicals and can cause DNA damage.

UV Radiation

Radiation that can cause thymine dimers, disrupting DNA replication.

Gene Duplication

The process by which a gene is duplicated, possibly leading to genetic variation.

Oncogene

A gene that has the potential to cause cancer when mutated or expressed at high levels.

Tumor Suppressor Gene

A gene that protects a cell from one step on the path to cancer; mutations can lead to cancer.