Gene Expression Regulation & Mutations

This set of flashcards covers key concepts related to gene expression regulation and mutations, providing definitions for important terms.

Prokaryotic Cells

Cells that control gene expression primarily by regulating transcription and can perform transcription and translation simultaneously.

Promoter

A DNA segment that allows a gene to be transcribed by helping RNA polymerase locate where the gene starts.

Operon

A section of DNA that includes a promoter, an operator, and structural genes that code for specific tasks, most commonly found in prokaryotes.

Lac Operon

An operon that consists of three genes involved in the breakdown of lactose, regulated like a switch based on lactose presence.

Lac Repressor

A protein that binds the operator region of the lac operon in the absence of lactose, blocking transcription.

Transcription Factors

Proteins and regulatory DNA sequences that initiate transcription in eukaryotic cells.

TATA Box

A conserved DNA sequence found in the promoter region that is important for initiating transcription in eukaryotes.

Enhancers

DNA sequences that increase the likelihood of transcription of particular genes.

Silencers

DNA sequences that decrease the likelihood of transcription of genes.

Sonic Hedgehog

A gene that plays a crucial role in embryonic development, first identified in fruit flies.

mRNA Cap

A specialized nucleotide added to the start of an mRNA strand that helps it bind to ribosomes.

mRNA Tail

A string of nucleotides added to the end of mRNA that facilitates its transport out of the nucleus.

Exons

Nucleotide sequences in the mRNA that code for proteins.

Introns

Nucleotide sequences in the mRNA that are removed before mRNA exits the nucleus.

Point Mutation

A mutation where one nucleotide is substituted for another in DNA.

Frameshift Mutation

Mutations that alter the reading frame of the genetic code, often resulting in more significant effects than substitution mutations.

Chromosomal Mutations

Mutations that affect many genes, often occurring during crossing-over.

Gene Duplication

A type of chromosomal mutation where a segment of DNA is duplicated, potentially leading to genetic diversity.

Translocation

A chromosomal mutation where segments of DNA from nonhomologous chromosomes exchange places.

Somatic Mutations

Mutations that occur in body cells and do not affect offspring.

Germline Mutations

Mutations that occur in gametes and can affect offspring, potentially beneficial or harmful.