Regulation of Gene Expression

These flashcards cover key vocabulary and concepts related to the regulation of gene expression discussed in the lecture notes.

Regulation of Gene Expression

The mechanisms by which cells switch the processes of transcription and translation on and off.

Lac Operon

A classical example of gene regulation discovered by Jacob and Monod, responsible for lactose metabolism in E. coli, expressed in the presence of lactose and absence of glucose.

Operon

A group of genes working together under the control of a single promoter, expressed together with related functions.

Epigenetic regulation

The control of gene expression through chemical modifications of DNA bases and the chromosomal superstructure without altering the DNA sequence.

DNA Methylation

The addition of a methyl group to cytosine residues in DNA, primarily suppressing gene expression.

Histone Acetylation

The addition of acetyl groups to lysine residues of histones, leading to relaxation of chromatin and increased gene transcription.

Inducible System

A system that is normally switched off and is activated in the presence of an inducer molecule.

Repressible System

A system that is normally switched on but can be switched off in the presence of a co-repressor.

Negative Gene Regulation

An active regulatory protein that turns gene expression off, such as the lac repressor.

Positive Gene Regulation

An active regulatory protein that turns gene expression on, such as cAMP in the lac operon.

Trp Operon

An operon that promotes the production of the amino acid tryptophan, which is switched off in the presence of tryptophan.

Non-disjunction

A mistake during cell division where chromosomes fail to separate properly, leading to aneuploidy.

Aneuploidy

A change in the number of individual chromosomes, which can lead to genetic disorders.

Down Syndrome

A common trisomy (Trisomy 21) caused by non-disjunction of chromosome 21, characterized by distinct facial features and developmental delays.