Lecture 2 - Genotype and Phenotype

Question 1

Why do bacteria not express all their genes all the time?

Answer 1

if bacteria expressed all genes at same time there would be conflicting information
cost of expression: waste of energy and use of C, N, P. Bacteria have limited food supply so need to use that supply optimally to only make those proteins that would be of benefit to them

Question 2

What is an operon?

Answer 2

one regulatory region controls expression of more than one gene. Facilitates a coordinated response; gene products functionally linked

Question 3

What is a regulon?

Answer 3

all the genes that fall under the control of a specific (global) regulatory protein. Facilitates coordinated expression.
operons under primary control

Question 4

What is a modulon?

Answer 4

group of genes that can respond to a common regulatory protein even though they may also be members of different regulons

Question 5

What is a stimulon?

Answer 5

group of genes that all respond to the same environmental signal