Lecture Notes on Control of Gene Expression

This set of flashcards covers key vocabulary and concepts related to the control of gene expression, focusing on the mechanisms in prokaryotic and eukaryotic cells.

Control of Gene Expression

The process by which a cell regulates the expression of specific genes to control the manufacture of various proteins.

Central Dogma of Molecular Biology

Describes the flow of genetic information in cells: DNA transcribes to RNA, which translates to protein.

Gene Expression

The conversion of genotype (genetic code) into phenotype (observable characteristics) through transcription and translation.

Regulatory Proteins

Proteins that influence the transcription of specific genes by enhancing or inhibiting the binding of RNA polymerase to DNA.

Transcription Initiation

The first step of gene expression where RNA polymerase binds to the promoter region of the gene and starts transcribing RNA.

Operon

A cluster of functionally related genes that can be controlled by a single on-off switch, allowing efficient gene regulation.

Positive Control

Regulatory process that increases the frequency of gene transcription, often mediated by activators.

Negative Control

Regulatory process that decreases the frequency of gene transcription, mediated by repressors binding to operators.

Inducible Operon

An operon that is usually off but can be turned on in response to an environmental signal (e.g., lac operon).

Repressible Operon

An operon that is usually on but can be turned off by an environmental signal (e.g., trp operon).

Catabolic Activator Protein (CAP)

A protein that binds to the CAP site of a promoter to enhance RNA polymerase binding, facilitating gene transcription.

cAMP (cyclic AMP)

A second messenger molecule that indicates low glucose levels, signaling the cell to activate pathways for energy utilization.

Transcription Factors

Molecules necessary for the initiation of transcription, which can be general or specific depending on their role.

Chromatin

Complex of DNA and proteins that helps package DNA into a compact, dense shape; its structure can impact gene expression.

Allolactose

An isomer of lactose that acts as an inducer in the lac operon, allowing transcription to occur by inhibiting the repressor.

Diauxic Growth Curve

A growth pattern observed in bacteria utilizing two sugars, characterized by two distinct growth phases when one substrate is depleted and the other is utilized.

Feedback Loop

Regulatory mechanism where the output of a system modulates its own production, as seen in the lac operon control.