MICRO CHAPTER 7

DNA-Binding Proteins

Proteins that bind to specific DNA sequences and are involved in transcription regulation.

Operon

A group of genes that are transcribed together under the control of a single promoter.

Transcription Factors

Proteins that control the rate of transcription by binding to specific DNA sequences.

Repressor Protein

A protein that binds to an operator region of DNA and blocks transcription.

Activator Protein

A protein that binds to DNA and enhances transcription.

Effector

A small molecule that influences the activity of regulatory proteins.

Allosteric Protein

A protein whose function is regulated by the binding of an effector molecule at a site other than the active site.

Corepressor

A small molecule that cooperates with a repressor protein to turn off transcription.

Inducer

A molecule that binds to a repressor or activator protein, facilitating transcription.

Helix-turn-helix

A common motif in DNA-binding proteins consisting of two alpha helices connected by a short sequence.

Zinc Finger

A type of DNA-binding domain that binds zinc ions and is often found in eukaryotic regulatory proteins.

Leucine Zipper

A structural motif in some proteins that facilitates dimerization and DNA binding.

Two-Component Regulatory System

A regulatory system consisting of a sensor kinase and a response regulator that transmits environmental signals.

Chemotaxis

Movement of an organism toward or away from a chemical stimulus.

Quorum Sensing

A regulatory mechanism in bacteria that allows them to communicate and coordinate group behaviors based on population density.

Feedback Inhibition

A mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway.

Riboswitch

A segment of messenger RNA that can bind a small molecule and alter gene expression.

Attenuation

A transcriptional control mechanism that prevents the completion of transcription based on the presence of specific metabolites.

Post-Translational Modification

The chemical modification of a protein after its translation, which can affect its activity.

Anti-sigma Factor

A protein that inhibits the activity of a sigma factor, affecting RNA polymerase activity.

Transcription

The process of synthesizing RNA from a DNA template.

RNA Polymerase

An enzyme that synthesizes RNA from a DNA template during transcription.

Messenger RNA (mRNA)

The RNA molecule that carries genetic information from DNA to the ribosome for protein synthesis.

Ribosomal RNA (rRNA)

A type of RNA that, together with proteins, makes up the ribosome.

Transfer RNA (tRNA)

The RNA molecule that transports amino acids to the ribosome during protein synthesis.

Promoter

A DNA sequence that initiates transcription of a gene by providing a binding site for RNA polymerase.

Enhancer

A DNA sequence that increases the likelihood of transcription of a particular gene by providing binding sites for transcription factors.

Silencer

A DNA sequence that can inhibit transcription when bound by specific proteins.

DNA Methylation

The addition of a methyl group to DNA, often leading to gene silencing.

Histone Modification

The chemical alteration of histone proteins that can influence gene expression by altering chromatin structure.

Chromatin Remodeling

The dynamic process of restructuring chromatin that allows for access to DNA for transcription.

Post-Transcriptional Regulation

The control of gene expression at the RNA level, influencing RNA stability and translation.

MicroRNA (miRNA)

Small RNA molecules that regulate gene expression by targeting mRNA for degradation or translation inhibition.

Small Interfering RNA (siRNA)

Short double-stranded RNA molecules that can lead to the silencing of specific genes through RNA interference.

Gene Expression

The process by which information from a gene is used to synthesize functional gene products, typically proteins.

Transcriptional Bursting

A phenomenon where genes are transcribed in bursts, leading to variability in gene expression.

Splicing

The process of removing introns and joining exons in pre-mRNA to produce mature mRNA.

Alternative Splicing

A process that allows a single gene to code for multiple proteins by rearranging exons during mRNA processing.

Nuclear Pore Complex

A large protein complex that regulates the transport of molecules between the nucleus and the cytoplasm.

Signal Transduction Pathway

A series of molecular events initiated by a signal that leads to a cellular response, often affecting gene expression.

Chromatin

The complex of DNA and protein found in eukaryotic cells that packages DNA into a more compact, denser shape.