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Gene Expression Control | BCHM - Biochemistry, Quizzes of Biochemistry

Class: BCHM - Biochemistry; Subject: Biochemistry; University: Student and Learning Services, Sheffield Hallam University; Term: Forever 1989;

Typology: Quizzes

2012/2013

Uploaded on 05/14/2013

amygouldsbrough
amygouldsbrough 🇬🇧

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TERM 1
Why Control Gene Expression?
DEFINITION 1
Every cell has same genetic infoDifferent cells need to do
different thingsGenes need to be turned on and off
TERM 2
Control of Gene Expression (simple terms)
DEFINITION 2
Prokaryotes EukaryotesTranscription Factors Enhancers
andupstream elements Nucleosomes DNA methylation
TERM 3
Transcription Factors
DEFINITION 3
TF are proteins that alter gene expressionActivators - bind
DNA and activate (increase) gene expressionRepressors -
bind DNA and repress (decrease) gene expressionBind near
start of gene with other proteins that alter gene expression
TERM 4
Enhancers and upstream elements
DEFINITION 4
Transcription factors that can bind far away from the
promoter toDISTAL ENHANCERSUPSTREAM ELEMENTS
TERM 5
Nucleosomes
DEFINITION 5
Eukaryotes - chromatin made up of nucleosomesDNA - tightly
packaged - harder for transcription factors and RNA
polymerase to access it because of this
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Why Control Gene Expression?

Every cell has same genetic infoDifferent cells need to do different thingsGenes need to be turned on and off TERM 2

Control of Gene Expression (simple terms)

DEFINITION 2 Prokaryotes EukaryotesTranscription Factors Enhancers andupstream elements Nucleosomes DNA methylation TERM 3

Transcription Factors

DEFINITION 3 TF are proteins that alter gene expressionActivators - bind DNA and activate (increase) gene expressionRepressors - bind DNA and repress (decrease) gene expressionBind near start of gene with other proteins that alter gene expression TERM 4

Enhancers and upstream elements

DEFINITION 4 Transcription factors that can bind far away from the promoter toDISTAL ENHANCERSUPSTREAM ELEMENTS TERM 5

Nucleosomes

DEFINITION 5 Eukaryotes - chromatin made up of nucleosomesDNA - tightly packaged - harder for transcription factors and RNA polymerase to access it because of this

DNA Methylation

methylation reduces gene expressiontends to occur on CpG islands - upstream of promoters TERM 7

Prokaryotic Gene

Organisation

DEFINITION 7 Prokaryotes have their genes organised into operonsOperon is a genetic unit that encodes one/more related genes that are transcribed as a single,polycistronicmRNAOperons expression is controlled by transcription factors TERM 8

trp Operon

DEFINITION 8 controls production of tryptophan in E coliTrpR is a transcription repressorRepresses transcription of the trp operon when tryptophan is presentTrpR regulates four other operons TERM 9

lac Operon

DEFINITION 9 controls production of lactose in E colilacZ = Beta galactosidase. Cleaves bond between galactose and glucose.LacY = Lactose permease. Transports lactose into the cell.LacA = Betagalactosidasetransacetylase. Role in hydrolysis. TERM 10

more details

DEFINITION 10 Lactose breaks down into > glucose and galactoseE coli prefers metabolisingglucose > lactose