Chapter 11 – The Expression of Genetic Information via Genes II: Non-coding RNAs

These flashcards cover key concepts, terms, and processes related to non-coding RNAs and their functionalities as discussed in Chapter 11.

Non-coding RNAs (ncRNAs)

RNA molecules that do not encode polypeptides but play various roles in cellular processes.

Ribozyme

An RNA molecule with catalytic function, capable of catalyzing specific biochemical reactions.

Scaffold

The function of some ncRNAs to bind multiple components such as proteins, facilitating the formation of a complex.

Guide

A mechanism by which ncRNAs direct other molecules to specific locations within the cell, such as guiding proteins to DNA.

Blocker

An ncRNA that prevents or blocks a cellular process, such as inhibiting translation by obstructing ribosome binding.

Decoy

An ncRNA that binds to target ncRNAs, preventing them from functioning.

CRISPR-Cas system

A bacterial system for defending against bacteriophages and transposons, involving the adaptation, expression, and interference phases.

TERC (telomerase RNA component)

An ncRNA that assists telomerase in binding to telomeres and serves as a template for DNA replication.

HOTAIR

An ncRNA that regulates gene expression by guiding histone-modifying complexes to specific genes, altering chromatin structure.

RNA interference (RNAi)

A biological process in which RNA molecules inhibit gene expression or translation, typically by causing the degradation of mRNA.

Signal recognition particle (SRP)

An RNA-protein complex that directs polypeptides to their proper location in the cell, such as the endoplasmic reticulum.

Double-stranded RNA (dsRNA)

A form of RNA that is more effective than antisense RNA at silencing target mRNAs.

MicroRNAs (miRNAs)

Small, endogenous ncRNAs that regulate gene expression by binding to complementary sequences on target mRNAs.

Small-interfering RNAs (siRNAs)

Exogenous ncRNAs that are typically perfectly complementary to their target mRNA, used in gene silencing.

Telomeres

Repeat sequences at the ends of linear eukaryotic chromosomes that protect them from damage.

Adaptation phase

The first phase of the CRISPR-Cas system in which bacterial cells recognize and integrate foreign DNA from bacteriophages.

Expression phase

The second phase of the CRISPR-Cas system where the genes involved are transcribed and processed to create crRNA.

Interference phase

The final phase of the CRISPR-Cas system, where the crRNA guides the Cas9 protein to target and cleave foreign DNA.

Which cellular compartment does the Signal Recognition Particle (SRP) primarily direct polypeptides to for synthesis?

The endoplasmic reticulum.

What is the primary function of crRNA in the CRISPR-Cas system?

crRNA guides the Cas9 protein to specific foreign DNA sequences for cleavage.

What is a key difference between microRNAs (miRNAs) and small-interfering RNAs (siRNAs) regarding their origin and complementarity to target mRNA?

miRNAs are endogenous and typically have imperfect complementarity to their target mRNA, while siRNAs are exogenous and usually perfectly complementary.

What is the consequence of HOTAIR guiding histone-modifying complexes to specific genes?

It alters chromatin structure, thereby repressing gene expression.

Why is double-stranded RNA (dsRNA) more effective than antisense RNA at silencing target mRNAs?

dsRNA is more stable and better recognized by the cellular machinery involved in RNA interference (RNAi), leading to more efficient degradation of target mRNA.