Gene Regulation

Apoptosis

A programmed cell death process that occurs in multicellular organisms, characterized by cell shrinkage, chromatin condensation, and DNA fragmentation. It is a crucial mechanism for maintaining cellular homeostasis and eliminating damaged or unnecessary cells.

Barr body

condensed, inactivated X-chromosome found in the cells of female mammals, which serves to balance the dosage of X-linked genes between males and females.

Cancer

a group of diseases characterized by uncontrolled cell growth and divison.

Carcinogen

any substance agent that can cause cancer by promoting the transformation of normal cells into cancerous cells.

Corepressor

a molecule that binds to a repressor protein and enhances it's ability to inhibit gene Expression, effectively preventing transcription of specific genes

Euchromatin

a loosely packed form of chromatin that is accessible for transcription, allowing for active gene expression.

Frameshift Mutation

a genetic mutation caused by the insertion or deletion of nucleotides in a DNA sequence that alters the reading frame of the gene

Genome

complete set of genetic material (DNA) in an organism, including all of its genes and noncoding sequences housed w/in its chromosomes

Growth Factor

naturally occuring substance, typically a protein, that stimulates cell growth, proliferation and differentiation

Heterochromatin

tightly packed form of chromatin that is generally transcriptionally inactive

Inducer

a molecule that initiates the expression of a gene by binding to a repressor protein and inactivating it, allowing transcription to proceed.

Inducible Operon

type of operon that is normally off but can be turned on (induced) in response to specific stimuli

Oncogene

mutated or overexpressed gene that has the potential to cause cancer

Operator

segment of DNA w/in an operon that acts as a binding site for a repressor protein, controlling the transcription of adjacent genes

Operon

cluster of genes under the control of a single promoter and regulated together typically found in prokaryotic genomes

Point Mutation

A change in a single nucleotide base pair in DNa which may result in a different amino acid being incorporated into a protein

Posttranscriptional control

Regulatory mechanism that occur after the transcription of DNA into mRNA, influencing the mRNA stability

Post Translational control

Regulatory mechanism that occurs after the translation of proteins affecting protein activity, stability and localization

Promoter

A DNA sequence that serves as a binding site from RNA polymerase and other transcription factors to initiate transcription of a gene.

Proto-oncogene

normal gene that can become an oncogene due to mutations or increased expression

Regulator Gene

a gene that is involved in the control of the expression of one or more other genes. It does not typically encode a protein that is directly involved in metabolic pathways or structural functions.

Repressible Operon

type of operon that is normally active but can be turned off in response to certain signals

Repressor

protein that binds to the operator of an operon to block transcription of the associated genes

Structural Gene

gene that encodes a protein or RNA molecule that has a direct role in structure of function of the cell

Transcription Factor

protein that binds to specific DNA sequences to regulate the transcription of genes

Transcriptional Control

regulatory mechanism that determine the rate of transcription of a gene; influencing how much mRNA is produced and hence how much protein is synthesized

Translational Control

regulatory mechanism that influence the efficiency and rate of translation of mRNA into proteins, affecting protein synthesis w/out altering transcription levels

Tumor

an abnormal mass of tissue that arises from excessive cell growth and division

Tumor Suppressor Gene

a gene that encodes proteins that help regulate cell growth and division, preventing tumor formation.