Regulation of Transcription and Translation Flashcards
1
Q
what is the transcription of genes controlled by?
A
- protein molecules called transcription factors
2
Q
what is the role of transcription factors in eukaryotes?
A
- transcription of target genes can be stimulated or inhibited when transcription factors move from cytoplasm to the nucleus
3
Q
what happens in the nucleus of cells?
A
- transcription factors bind to specific DNA sites called promoters, promoter regions
4
Q
what are examples of transcription factors?
A
- activators (stimulates or increases rate of transcription)
- repressors (inhibits or decreases rate of transcription)
5
Q
what is oestrogen?
A
expression of genes can be affected by other molecules in cells, such as oestrogen
- a steroid hormone which can affects transcription by binding to transcription factors called oestrogen receptors
- forms an oestrogen-oestrogen receptor complex
6
Q
what does the oestrogen-oestrogen receptor complex do?
A
- complex moves from cytoplasm into nucleus where it binds to specific DNA sites near start of target gene
- complex can act as an activator of transcription
7
Q
what does siRNA stand for?
A
small interfering RNA
8
Q
where does siRNA join?
A
by complementary base pairing to mRNA
9
Q
how does siRNA work?
A
- once mRNA is transcribed, it leaves nucleus for cytoplasm
- in cytoplasm, double stranded siRNA associates with and unwinds
- one of the single strands of siRNA is selected and other is broken down
- single strand of siRNA binds to target mRNA
- proteins associated with siRNA cut mRNA into fragments
10
Q
what is used to control teen expression?
A
- increased methylation of DNA
- decreased acetylation of histones
11
Q
A
