BIO130 Exam 3

DNA function

Stores info to run cell

RNA function

Make proteins

Protein function

Actually do the work in the cell

mRNA

Contains genetic info (transcript)

tRNA

Recognises info in mRNA and carries corresponding amino acids

rRNA

Part of the ribosome, brings tRNA and mRNA together, covalently links amino acids

Regulatory Sequence

Site for binding regulatory proteins, influences rate of transcription

Promoter

Signals beginning of transcription

Transcribed region

Contains info for amino acid sequence

Terminator

Signals end of transcription

mRNA Transcription Stages

Initiation, elongation, termination

Preinitiation Complex Parts

GTFs, RNA Polymerase II, minimum machinery needed for basal transcription

Core promoter

Sequence of DNA where proteins bind to initiate transcription

TATA Box

Directs RNA pol. II to start transcription precisely at start site

Enhancer

Recruits PIC subunits to increase level of activity

Repressors

Physically blocks transcription by binding to DNA

Silencer

Sequence of nucleotides to attract repressors

Distal activators

Direct binding or mediator complex

Chromatin remodelling

changes nucleosome structures (moves nucleosomes, removes histomes, replaces histomes)

Acetyl group

Loosens DNA wrapping

Epigenetics

Modifications to control gene expression, heritable

Imprinting

Marking chromosomes and turning off specific genes without changing nucleotide sequence

DNA Methylation

On cytosine, inactivates gene expressions