topic 8 regulation of transcription and translation Flashcards
what is transcription?
where a gene is copied from DNA into mRNA
what is the role of RNA polymerase?
to synthesise mRNA from DNA
what is a transcription factor?
a protein that controls the transcription of genes by binding to a specific region of DNA
how do transcription factors work?
transcription of target genes can be stimulated or inhibited when specific transcriptional factors move from the cytoplasm to the nucleus
can turn on/off genes so only certain proteins are produced in a particular cell
how do transcriptional factors initiate transcription?
by binding to different base sequences on DNA
what happens once a transcriptional factor has attached?
transcription begins
creates an mRNA molecule for that gene
which can be translated in the cytoplasm to create a protein
what happens if a transcription factor doesn’t bind?
gene is inactive and the protein won’t be made
what is an example of a transcription factor?
oestrogen
what is oestrogen?
steroid hormone that can initiate transcription
what does an activator do?
increase transcription?
what does a repressor do?
decrease transcription
how does oestrogen act as a transcription factor?
lipid soluble so can freely diffuse across the cell membrane where it binds to a receptor molecule on a transcription factor
binding alters the shape of the DNA binding site on the transcription factor so it can bind to the DNA
transcription factor therefore enters the nucleus via the nuclear pore where it binds to the DNA, which stimulates the transcription of the gene making up DNA
