Regulation Of Gene Exression

Question 1

What controls amount of protein produced?

Answer 1

RNA polymerase

Question 2

Repressors (3)

Answer 2

Repress transcription of nearby genes
May act through more than one mechanism
To ensure robust and efficient repression

Question 3

Co repressors (2)

Answer 3

Repressors that do not bind to DNA themselves

Instead assemble in DNA-bound regulatory proteins

Question 4

Enhancers (6)

Answer 4

Contain several transcriptional bounding sites
They attract, position and modify the general transcription factors
And RNA polymerase II at the promoter
So that transcription can begin
May also modify local chromatic structure
To aid transcription

Question 5

TATA box (core promoter) (5)

Answer 5

Located -25 to -35 nucleotides from transcription start site
Has a variant sequence 5’-TATAAA-3’
Which is often followed by 3 or more adenine bases
Bound by TATA binding protein
Facilitates unwinding unwinding of the DNA

Question 6

TATA mechanism (6)

Answer 6

Transcription factor TTIID binds to TATA box
Followed by TFIIA upstream and TTIIB downstream
This protein compels binds to RNA polymerase
Other transcriptional factor bind to complex
This forms the basal transcriptional complex
Transcription begins

Question 7

Response element sequences (4)

Answer 7

Short sequences in the promoter region
That can bind specific transcription factors to alter transcription
Allows for coordinated response to a single stimuli
Only elements under 50 base pairs of start point for transcription are fixed in location

Question 8

Oestrogen receptor response element (8)

Answer 8

Oestrogen can alter the expression of many genes
Oestrogen can pass directly through membranes to the nucleus
Binds to oestrogen receptor
Which binds to oestrogen response element
Oestrogen receptor in absence of oestrogen recruits histone deacetylase
Which switches off gene
When oestrogen is bound to receptor histone acetylase is recruited
Which switches gene on

Question 9

CAAT and GC box position

Answer 9

Positioned between -70 and -200

Question 10

Transcription overview (7)

Answer 10

Process by which info in DNA is copied to a molecule of RNA
Carried out by RNA polymerase
And transcription factors
Transcription factors bind to promoters and enhancers
To recruit RNA polymerase to transcription site
Transcription is initiated
RNA polymerase makes mRNA

Question 11

RNA polymerase

Answer 11

Enzyme that is used to transcribe DNA into RNA

Question 11

Primer (3)

Answer 11

Short nucleic acid sequence
That provides a starting point of DNA synthesis
Synthesised by the enzyme primase

Question 11

Promoter (5)

Answer 11

DNA sequences that define where transcription begins
Typically located at the 5’ end of the transcription initiation site
Bound by RNA polymerase and transcription factors
To initiate transcription
Promoter also indicates which DNA strand will be transcribed