Flashcards in Regulation Of Transcription And Translation Deck (15):
What is a transcriptional factor?
A specific molecule that moves from the cytoplasm into the nucleus and stimulates a gene by binding to a specific region of the DNA in the nucleus
What is required before transcription can begin?
The gene must be stimulated by a transcriptional factor
When a gene is not being expressed, what happens to the site on the transcriptional factor that binds to the DNA?
It is blocked by an inhibitor molecule
How can hormones like oestrogen start transcription?
They combine with a receptor on the transcriptional factor which releases the inhibitor molecule
How does oestrogen enter a cell?
It diffuses through the phospholipid bi-layer of the cell
Once inside the cytoplasm, what does the oestrogen combine with?
It combines with a complementary site on a receptor molecule of the transcriptional factor
What does the oestrogen do to release the inhibitor molecule from the DNA binding site?
It changes the shape of the receptor molecule
What can the transcriptional factor do once the inhibitor molecule has been released?
Enter the nucleus through a nuclear pore and combine with DNA
What does the combination of the transcriptional factor with DNA stimulate?
Transcription of the gene that makes up the portion of DNA
What is essential in breaking down mRNA to prevent gene expression?
What is siRNA?
Small, double stranded sections of RNA which breaks down mRNA
How is siRNA formed?
An enzyme cuts large double stranded molecules of RNA into smaller sections (siRNA)
What happens once the double stranded RNA has been broken up into siRNA?
One of the two strands of siRNA combines with an enzyme
How does the siRNA that has combined with the enzyme break the mRNA into sections?
The siRNA guides the enzyme to an mRNA molecule by pairing up with its complementary bases and the enzyme cuts the mRNA into smaller pieces