Gene Expression at the Molecular Level III: Gene Regulation

These flashcards cover key vocabulary related to gene expression and regulation, fundamental for understanding molecular biology concepts.

Gene expression

The process by which a gene is made into a functional product.

Gene regulation

The mechanisms that control the timing and amount of gene expression to produce proteins at the correct time and level.

Constitutive genes

Genes that have essentially constant levels of expression under all conditions.

E. coli

A type of bacteria that can metabolize various sugars, including lactose.

Lactose permease

A protein that transports lactose into E. coli cells.

β-galactosidase

An enzyme that breaks down lactose in E. coli.

Cell differentiation

The process by which cells become specialized in structure and function.

Gene regulation in eukaryotes

Involves factors such as transcription factors, changes in chromatin structure, and DNA methylation.

Transcription factors

Proteins that bind to DNA and help regulate gene expression.

Negative control

A regulation mechanism in which repressors inhibit transcription.

Positive control

A regulation mechanism in which activators enhance transcription.

Operon

A set of genes under the transcriptional control of one promoter; can be transcribed as polycistronic mRNA.

Lac operon

A set of genes in E. coli that are controlled together to metabolize lactose.

Allolactose

A small effector molecule that prevents the lac repressor from binding to the operator when lactose is present.

CAP (catabolite activator protein)

An activator protein that enhances transcription of the lac operon in the presence of cAMP.

trp operon

An operon in E. coli that encodes enzymes for the synthesis of tryptophan.

Corepressor

A substance that inhibits the expression of genes; tryptophan acts as a corepressor for the trp operon.

DNA methylation

A process by which methyl groups are added to DNA, usually inhibiting transcription.

Alternative splicing

The process by which a single gene can produce multiple mRNA transcripts by combining different exons.

Mediator

A protein complex that assists in the regulation of transcription by facilitating interactions between transcription factors and RNA polymerase.

Chromatin remodeling

The dynamic modification of chromatin architecture to allow access to DNA for transcription.

Transcriptional start site

The specific location on the DNA where RNA polymerase begins transcription.

Enhancers and silencers

Regulatory elements that increase or decrease transcription rates of associated genes respectively.