Regulation of Gene Expression Vocabulary

Flashcards reviewing key vocabulary related to gene expression and its regulation.

Histones, chromatin

DNA is packaged with proteins called ____, when packaged we call it ____.

Epistasis

When the expression of one gene masks the phenotype of another, this is called .

RNA polymerase

The enzyme responsible for transcription.

Ribosomes

Organelle responsible for translation.

Promoter

The DNA sequence where transcription begins.

Terminator

The DNA sequence where transcription ends.

Differential gene expression

Different cell types arise due to this, rather than differing genomes.

Histones

Modifications to these can regulate gene expression at the DNA level.

Epigenetic inheritance

Inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence.

Histone acetylation

The attachment of acetyl groups to histone tails, promoting loose chromatin structure and increased transcription.

DNA methylation

The addition of methyl groups to certain bases in DNA, associated with reduced transcription.

Noncoding RNAs (ncRNAs)

RNAs that are not translated into protein.

Long noncoding RNAs (lncRNAs)

Noncoding RNAs that are 200+ nucleotides long.

XIST

A lncRNA transcribed from the XIST gene that inactivates the X chromosome as Barr bodies.

Operons

In prokaryotes, transcription is commonly regulated using these structures.

Feedback inhibition

In prokaryotes, transcription is commonly regulated using this mechanism.

Operator

The segment of DNA that acts as an 'on-off switch' for an operon.

Repressor

A protein that can switch off the operon.

Repressible operon

An operon that is usually on, but can be switched off by a repressor.

Inducible operon

An operon that is usually off, but can be switched on by an inducer.

Corepressor

A small molecule that binds to a bacterial repressor protein and changes the protein's shape, allowing it to bind to the operator and switch an operon off.

Inducer

A specific small molecule that inactivates the repressor, leading to the expression of the genes in the operon.

Structural genes

Genes that code for proteins not involved in the regulation of gene expression.

Inducible enzymes

Enzymes that function in catabolic pathways, and their synthesis is induced by a chemical signal.

Repressible enzymes

Enzymes that function in anabolic pathways, and their synthesis is repressed by high levels of the end product.

Promoter

The binding site for RNA polymerase.

Regulatory gene

A gene that codes for a repressor protein.

Negative control

Type of control of genes in operons, that are switched off by the repressor.

Histone acetylation

The process of attaching acetyl groups to histone tails.

DNA methylation

The addition of methyl groups to DNA bases.