Modulating Transcription

Question 1

What is required for prokaryotic growth?

Answer 1

• nutrient rich environment containing amino acids and carbohydrates
• favourable temperatures

Question 2

Housekeeping Genes

Answer 2

• required all of the time for normal function
• include genes that are important for structural proteins of the cell, RNA/DNA polymerase and genes that code for ribosomal proteins

Question 3

Regulated Genes

Answer 3

can be turned off/on on an as-needed basis

Question 4

When _________ is absent, the cell can metabolize _________

Answer 4

glucose

lactose

Question 5

lactose is metabolized into glucose and galactose by

Answer 5

B-galactosidase

Question 6

How is B-galactosidase made?

Answer 6

by turning on transcription of the B-galactosidase gene (occurs when lactose is available)

Question 7

Mohod & Jacob

Answer 7

-observed that lactose had to be present in order for B-galactosidase to be produced

Question 8

Gene Expression

Answer 8

-functional product of the gene is made, modified and activated

Question 9

Transcriptional Control

Answer 9

• DNA to mRNA
• controls the amount to mRNA produced in the cell
• cell can activate or inhibit transcription by controlling the binding of proteins to a promoter
• has to transcribe, translate and modify the enzyme which takes longer
• doesn’t waster energy making polypeptide or mRNA unless needed

Question 10

Translational Control

Answer 10

• mRNA to Protein
• rate at which translation occurs affects amount of protein produced
• amount of protein produced depends on stability of mRNA

Question 11

Post-translational Control

Answer 11

• Protein to Activated Protein
• allow polypeptide to be folded into functional 3D structure
• more than a dozen post-translational modifications regulate the ability of the protein to become active or inactive by driving the assembly into complexes, the binding of substrates or the unmasking of enzymatic domains
• allows the cell to stockpile inactive proteins and turn them on when a signal is received