Explain how chromatin remodelling works in gene regulation
DNA cannot transcribe tightly coiled heterochromatin but can transcribe loosely coiled euchromatin present during interphase. This is why protein synthesis occurs at this stage.
1 of 16
Why do our cells use chromatin remodelling?
As it ensures the necessary proteins for cell division are synthesised in time so saves energy due to no protein synthesis occuring during cell replication
2 of 16
Explain histone modification for gene regulation
Negative DNA coils around positive histones. Histones can be modified so that DNA is more or less tightly coiled and therefore affects the rate of transcription
3 of 16
What is acetylation and what does it do?
The addition of acetyl or phosphate groups to reduce the positive charge of the histones causing DNA to coil less lightly so certain genes can be transcribed
4 of 16
DNA codes for _______ which codes for _______?
Genes, Proteins
5 of 16
What is methylation and what does it do?
The addition of methyl groups making histones more hydrophobic causing tighter binding and tighter coiling in the DNA. Prevents transcription of genes
6 of 16
What is an operon?
A group of genes under the control of the same regulatory mechanism so that they're all expressed at the same time
7 of 16
Explain the Lac Operon in gene regulation
A regulatory gene codes for a repressor protein which binds to the operator and stops RNA Polymerase binding to it. This prevents transcription of the structural genes needed for lactase production.
8 of 16
Why do we need the Lac Operon?
As it prevents wasting energy and resources by only producing lactase when it is needed due to the genes involved in their production being turned off
9 of 16
Explain what happens if lactose is present
Lactose binds to the repressor and changes it shape so it cannot bind to the operator. RNA Polymerase binds instead and transcription occurs.
10 of 16
Explain the role of Cyclic AMP (cAMP)
cAMP binds to CRP (camp receptor protein) so RNA Polymerase binds more tightly and rate of transcription increases
11 of 16
What happens to cAMP if glucose enters a cell
Lactose genes aren't transcribed as the [cAMP] decreases
12 of 16
What happens during RNA Processing and how does it help?
A cap is added to one end of the mRNA and a tail is added to the other. This stabilises it and slows downs rate of degradation
13 of 16
What is RNA editing?
The change of mRNA nucleotides by addition, substitution or deletion so that different proteins are made so that one mRNA molecule can make several proteins
14 of 16
What are protein kinases?
Enzymes that catalyse the addition of phosphate groups to proteins which then changes their tertiary structure and consequently the function
15 of 16
What does post-translational control involve?
The modification of proteins after they have been synthesised
16 of 16
Other cards in this set
Card 2
Front
Why do our cells use chromatin remodelling?
Back
As it ensures the necessary proteins for cell division are synthesised in time so saves energy due to no protein synthesis occuring during cell replication
Comments
No comments have yet been made