Lecture_geneticsII

Mutation

A change in the base sequence of DNA that can lead to a change in the end product.

Mutagen

Environmental agents that bring about mutations.

Wild type

The typical form of an organism as it occurs in nature.

Point Mutation

A mutation that involves a change in a single base pair in DNA.

Nonsense Mutation

A mutation where the codon codes for a stop codon.

Missense Mutation

A mutation that results in a different amino acid being incorporated into a protein.

Silent Mutation

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

Frameshift Mutation

A mutation caused by the insertion or deletion of one or more nucleotides which alters the reading frame.

Chemical Mutagen

A substance that causes changes in DNA due to its chemical structure.

Nucleoside Analogs

Chemically modified nucleotides that have different base-pairing properties.

Intercalating Agents

Compounds that insert between bases in the DNA structure.

Ionizing Radiation

X-rays and gamma rays that cause breaks in DNA molecules.

Nonionizing Radiation

UV radiation that causes thymine dimers.

Thymine Dimer

A covalent bond formed between adjacent thymine bases due to UV radiation.

Ames Test

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

Conjugation

The transfer of DNA between two bacteria through physical contact.

Transformation

The process of taking up foreign DNA from the environment by a bacterial cell.

Transduction

The transfer of DNA between bacteria via a virus.

Plasmid

Extra chromosomal, self-replicating, circular DNA molecules found in bacteria.

Lac Operon

A set of genes regulated together to metabolize lactose, expressed under specific conditions.

Repressor

A regulatory protein that blocks RNA polymerase from initiating transcription.

Inducer

A substance that initiates transcription of a gene.

RNA Polymerase

The enzyme responsible for synthesizing RNA from a DNA template.

Gene Regulation

The control of the timing and rate of gene expression.

Horizontal Gene Transfer

The transfer of genes between organisms in a manner other than traditional reproduction.