Gene Expression III - Gene Regulation (c14)

Question 1

gene regulation

Answer 1

the ability of the cell to control levels of gene expression

Question 2

metabolic control

Answer 2

control protein levels for enzymes that catalyze biochemical reactions

Question 3

response to environment

Answer 3

respond to environmental stimuli

Question 4

response to stress

Answer 4

respond to stressors in the cell

Question 5

conservation of energy

Answer 5

make only proteins that are necessary at any given time

Question 6

gene regulation in prokaryotes

Answer 6

prokaryotes are constantly regulating expression of metabolic genes in response to molecules in their environment

Question 7

when lactose is available, bacteria synthesizes what two proteins

Answer 7

lactose permease
B-galactosidase

Question 8

lactose permease

Answer 8

transports lactose into cell

Question 9

B-galactosidase

Answer 9

breaks down lactose

Question 10

gene regulation in eukaryotes

Answer 10

multicellular eukaryotes develop many different cell types with unique functions – cell differentiation

each eukaryotic cell type differentially regulates gene expression

all organisms cells contain same genome but express different proteomes

expression is differentially regulated during development

Question 11

difference between eukaryotic and prokaryotic gene regulation

Answer 11

prokaryotes uses lactose, all same cell
eukaryotes contain same genome but express different proteomes
only eukaryotes regulate gene expression at the post-transcriptional level

Question 12

housekeeping genes

Answer 12

genes that are ubiquitously expressed regardless of cell type

Question 13

most gene regulation occurs at . . .

Answer 13

transcriptional and post-translational levels in BOTH eukaryotes and prokaryotes

Question 14

transcriptional regulation in bacteria

Answer 14

involves transcription factors , repressors inhibit transcription of genes when not needed, activators activate transcription of genes when needed

Question 15

operon

Answer 15

a cluster of genes in bacteria that are under transcriptional control of one promoter

Question 16

operons in bacteria

Answer 16

allow coordinated regulation of a group of genes that share a common function

Question 17

lac operon

Answer 17

encodes a cluster of genes involved in lactose catabolism (lacZ, lacY, lacA)

Question 18

two transcriptional regulatory sites

Answer 18

cap site: bound by activator
operator (lacO): bound by repressor
lacyY codes for lactose permease: transports lactose into the cytosol
lacZ codes for B-galactosidase: breaks down lactose into galactose and glucose

Question 19

lac operon with no lactose

Answer 19

lac repressor binds the lacO operator and inhibits transcription

Question 20

lac operon with lactose

Answer 20

small amount of allolactose is made
Rna polymerase is now free to start transcription of the lac genes

Question 21

allolactose

Answer 21

a small molecule that binds and inhibits the lac repressor