8: Regulation of transcription Flashcards
1
Q
Why is it necessary to regulate gene expression
A
- Conserve resources
- Respond to changes in internal or external environments
- Ordered development (due to the various stages of gene expression)
2
Q
What is the definition of operons?
A
Set of co-transcribed genes under the control of a single regulated promoter
3
Q
What are two classes of genes
A
Housekeeping genes (not always expressed)
Constitutive genes always expressed
4
Q
Why should we regulate gene expression?
A
- It conserves resources
- Allows organisms to respond to changes in internal or external environments (nutrients, building blocks, toxins)
5
Q
Draw out the stages of gene expression
A
(look through slides)
6
Q
Describe how prokaryotes transribe/translate
A
- Prokaryotes lack a nucleus so they have coupled transmission and transcription of mRNA
- Transcription rate is 40N/s
- Translation 15 aa/s
- mRNAs are unstable and have an average half life of 2-3 minutes
(draw diagram from slides)
7
Q
Describe the features of operons (5)
A
slides
