Regulation of Gene Expression

Question 1

Define regulatory genes

Answer 1

Genes whose products regulate the expression of other genes. The products can inhibit or stimulate the expression of that gene.

If it inhibits expression, the regulation is negative ; if it stimulates expression, the regulation is positive.

Some products can be both positive and negative.

Question 2

Define regulon

Answer 2

Set of genes regulated by the same regulatory gene product

Question 3

What do you call a gene that regulates its own expression?

Answer 3

autoregulated

Question 4

Expression of a gene is often regulated by controlling the amount of mRNA made from the gene, what is this called?

Answer 4

Transcriptional regulation

Question 5

What is an operon?

Answer 5

a polycistronic unit that encodes for multiple structural/regulatory genes and includes a promoter and terminator

Question 6

Where does regulation of transcription occur?

Answer 6

Well obviously at the initial stages of replication where the promoter is. How else would mRNA be made. dumbass.

Question 7

How does a transcriptional repressor work?

Answer 7

Binds to the DNA on/near operator sequence and physicslly prevents rna pol from binding there

Question 8

How does a transcriptional activator work?

Answer 8

Usually by binding upstream of the promoter at an activator site to help RNA pol bind to the promoter

Question 9

Define effectors

Answer 9

Small molecules that affect the activity of regulatory proteins.

Can be inducers (causes transcription of operon to be turned on, maybe by binding to a repressor and changing its structure so that the repressor can no longer bind to the DNA)

or corepressor (causes operon to be turned off)

Question 10

What is posttranscriptional regulation

Answer 10

Regulation of the activity of a protein product by degradation using proteases or methylation… or feedback inhibition