Chapter 11 Gene expression 2

non-coding RNAs (ncRNAs)

RNA molecules that do not encode polypeptides and may play a variety of roles in cellular processes.

transcription

The process of synthesizing RNA from a DNA template.

translation

The process of synthesizing proteins based on the sequence of an mRNA template.

ribozyme

An RNA molecule that has catalytic activity, for example during peptide bond formation in ribosomes.

HOTAIR

A non-coding RNA that regulates gene expression by affecting chromatin structure.

telomerase

An enzyme that adds repetitive sequences to the ends of chromosomes, using an RNA component known as TERC.

TERC

Telomerase RNA component, which guides telomerase activity in extending telomeres.

scaffold

A role of some ncRNAs that bind to multiple components, facilitating the formation of molecular complexes.

blocker

A type of ncRNA that physically prevents cellular processes, such as the binding of ribosomes.

decoy

An ncRNA that sequesters other ncRNAs, preventing them from functioning.

microRNAs (miRNAs)

Small non-coding RNA molecules that regulate gene expression by binding to complementary sequences on mRNA.

small-interfering RNAs (siRNAs)

Short, double-stranded RNA molecules that can degrade mRNA and silence gene expression.

RNA interference (RNAi)

A biological process in which RNA molecules inhibit gene expression or translation.

Signal Recognition Particle (SRP)

A ribonucleoprotein complex that helps target polypeptides to the endoplasmic reticulum.

CRISPR-Cas system

A bacterial defense mechanism that uses RNA and associated proteins to detect and destroy foreign genetic material.

adapter

The stage in the CRISPR-Cas system where foreign DNA is inserted into the CRISPR array.

interference phase

The final phase of the CRISPR-Cas system where the complex cleaves foreign DNA.

spacer sequences

Unique sequences interspersed between repeats in the CRISPR array that are derived from previous infections.

telomeres

Repeated DNA sequences at the ends of chromosomes that protect them from degradation.

chromatin

A complex of DNA and protein found in eukaryotic cells, which can be remodeled by ncRNAs.

GTPase activity

An enzymatic activity that hydrolyzes GTP to GDP, crucial for the function of SRP.

polypeptide

A polymer of amino acids joined together, serving as a precursor to proteins.

programmed cell death

A controlled process of cell elimination, often related to telomere shortening.

histone modifications

Chemical changes to histone proteins that affect gene expression by altering chromatin structure.

complementary base pairing

The specific hydrogen bond interactions between nucleotide bases (A-T and G-C) that stabilize RNA and DNA.

stem-loop structure

A secondary structure in RNA formed by base pairing within the same strand, often involved in binding proteins.

nucleotide sequence

A specific order of nucleotides in a nucleic acid that encodes genetic information.

catalyst

A substance that increases the rate of a reaction without being consumed, often type of enzyme.

oncogene

A gene that has the potential to cause cancer, typically through mutations that lead to overactivity.

tumor-suppressor gene

A gene that protects a cell from one step on the path to cancer; when defective, can contribute to tumor development.

bacteriophage

A virus that infects and replicates within bacteria.

genetic information

The information encoded in genes that governs the traits and functions of living organisms.

macromolecules

Large complex molecules, which include proteins, nucleic acids, carbohydrates, and lipids.