Ls1b Lecture 2 Flashcards

Gene

A segment of DNA that encodes a functional RNA or protein.

Transcription

The process of copying DNA into RNA by RNA polymerase.

Transcriptional Unit

A section of DNA transcribed into a single RNA molecule.

DNA

The molecule that stores genetic information.

mRNA (Messenger RNA)

RNA that carries genetic instructions from DNA to ribosomes for protein synthesis.

Template Strand

The DNA strand that serves as a template for RNA synthesis.

Non-template Strand (Coding Strand)

The DNA strand with the same sequence as the RNA (except thymine replaces uracil).

Polypeptide (Protein)

A chain of amino acids translated from mRNA.

Promoter

A DNA sequence where RNA polymerase binds to initiate transcription.

Core/Minimal Promoter

A general DNA sequence near the transcription start site containing binding sites for general transcription factors

Regulatory Promoter

A specific DNA sequence upstream of the core promoter that binds transcription factors (activators and repressors) to regulate gene expression.

RNA-Coding Region

The portion of DNA transcribed into RNA.

Transcription Start Site

The location where RNA synthesis begins.

Terminator

A DNA sequence signaling RNA polymerase to stop transcription.

Transcription Termination Site

The point where RNA synthesis ends.

Upstream

DNA sequences before (5’ to) the transcription start site.

Downstream

DNA sequences after (3’ to) the transcription start site.

Gene Regulation

Control of gene expression at transcriptional and post-transcriptional levels.

Transcriptional Repressor

A specific protein that inhibits gene transcription by binding to regulatory DNA elements and blocking RNA polymerase.

Transcriptional Activator

A specific protein that enhances gene transcription by binding to regulatory DNA elements.

Transcription Factor (Activator/Repressor) Binding Site

A specific DNA sequence where regulatory proteins bind to control transcription.

Enhancer

A specific DNA sequence that increases transcription levels by binding to activators.

RNA Polymerase

The enzyme that synthesizes RNA from a DNA template.

TFIID (General Transcription Factors)

A general protein complex that helps RNA polymerase bind to the promoter.

Intron

A non-coding sequence of DNA that is removed during RNA processing.

Exon

A coding sequence of DNA that remains in the final mRNA.

Splicing

The process of removing introns and joining exons in mRNA.

Alternative Splicing

The process by which different combinations of exons are joined to create multiple proteins from a single gene.

Cytoplasm

The part of the cell where translation occurs.

Nuclear Pore

The passage through which mRNA exits the nucleus.

RNA Interference (RNAi)

A process where small RNAs regulate gene expression by inhibiting mRNA translation or causing degradation.

Single-Stranded RNA (ssRNA)

RNA consisting of only one strand.

Double-Stranded RNA (dsRNA)

RNA with two complementary strands

Small Interfering RNA (siRNA)

A highly specific type of RNA that silences a specific mRNA by targeting it for degradation.

Micro RNA (miRNA)

A less specific small RNA molecule that regulates multiple genes by inhibiting translation.

Dicer

An enzyme that cuts dsRNA into short RNA fragments (siRNA and miRNA).

RISC (RNA-Induced Silencing Complex)

A protein complex that guides siRNA or miRNA to target mRNA.

Guide RNA

The RNA strand within RISC that base-pairs with target mRNA.

mRNA Cleavage

The cutting of mRNA

mRNA Degradation

The breakdown of mRNA to prevent protein production.

Inhibition of Translation

Blocking ribosomes from translating mRNA into protein.

Activator

A specific protein that increases transcription of a gene by binding to regulatory DNA elements.

Repressor

A specific protein that decreases transcription by binding to regulatory DNA elements and blocking RNA polymerase.

TATA Box

A general DNA sequence found in many core promoters that helps initiate transcription.

TBP (TATA Binding Protein)

A general transcription factor that binds to the TATA box and helps recruit RNA polymerase.