Regulation of Gene Expression

A set of flashcards covering key concepts, processes, and mechanisms involved in the regulation of gene expression.

What is cell differentiation?

The change of a precursor cell into a specialized cell type.

What mostly controls differentiation of cells?

Differentiation is controlled by which genes are expressed in the cells.

What occurs during transcription?

Transcription is the process of copying RNA from a DNA template.

In which direction does transcription proceed?

Transcription proceeds in the 5' to 3' direction.

What is the role of RNA polymerase?

RNA polymerase catalyzes the reaction of linking adjacent nucleotides.

What are the components that determine the start and stop sites for a gene?

Specific DNA sequences determine the start and stop site for a gene.

What kind of proteins recognize start and stop sequences on DNA?

DNA binding proteins bind to specific sequences.

What are enhancer elements?

Cis-acting regulatory sequences that can regulate transcription through the binding of transcription factors.

What is the role of transcription factors in transcriptional regulation?

Transcription factors help initiate transcription by binding to specific DNA sequences.

What is the lac operon?

A model for transcriptional regulation in prokaryotes such as E. coli.

What happens in the lac operon in the absence of lactose?

The repressor protein binds to the operator site, blocking transcription.

What induces the expression of enzymes necessary for lactose metabolism?

The presence of lactose induces expression of these enzymes.

What is meant by a polycistronic mRNA?

An mRNA that contains coding sequences for multiple proteins.

What is a constitutive promoter?

A promoter that is always active, leading to continuous expression of its associated gene.

What is histone acetylation?

The addition of acetyl groups to histone proteins that promotes a loose chromatin structure, allowing transcription.

What is the role of DNA methylation in gene expression?

DNA methylation typically represses transcription and is an example of epigenetic regulation.

What is a transcription factor's activation domain?

The part of the protein that mediates the activation of transcription initiation.

How do steriod hormones regulate transcription?

Steroid hormones bind to their receptors, which act as transcription factors to activate transcription.

What does chromatin remodeling achieve?

It alters the packaging of DNA to regulate gene accessibility for transcription.

What is an example of a signaling cascade that regulates transcription factors?

Phosphorylation cascades, such as those activated by G-protein coupled receptors.

What is the role of the Myc-Max system in cell division?

Myc activates transcription of genes necessary for cell division when expressed, while Max can inhibit transcription when it forms homodimers.

What is an operon?

A cluster of genes transcribed together from the same promoter.