Lesson 5- Controlling Gene Expression

Question 1

why does protein synthesis need to be regulated?

Answer 1

time, energy, resources. living things must respond to their environment effectively

Question 2

transcriptional regulation

Answer 2

1. activator molecule binds to a sequence upstream of the gene’s promoter and signals a protein ~remodelling complex~ where histone core proteins dissociate from DNA and expose promoter
2. activators and repressors can bind to the promoter to slow down or speed up transcription
3. ~methyl group~ is added to cytosine bases of promoters and inhibits transcription by blocking rna polymerase until needed (silencing, on hold)

Question 3

post-transcriptional regulation

Answer 3

1. ~alternative splicing~ removes different combinations of introns of mRNA where remaining exons are spliced together
2. bind ~masking proteins~ to mRMA to keep inactive form and not undergo protein synthesis (other proteins can remove when ready to use)
3. change ~rate~ of degradation with presence of the hormone prolactin (lifespan of casein mRNA is extended)

Question 4

translational regulation

Answer 4

change (add to or delete from) poly-A-tail to increase or decrease translation

Question 5

post-translational regulation

Answer 5

1. ~processing~ removes specific sections of protein tp make it active
2. ~chemical modification~ are chemical groups added or deleted (on hold) and when ready these groups are deleted or added to carry out the proteins function
3. ~degradation~ of proteins and are recycled to create new proteins. they have a protein tag called ubiquitin and add/remove can extend or shorten functional life. some proteins can last an entire lifetime