13.1

Question 1

prokaryotes regulate gene expression

Answer 1

in response to enviromental changes

Question 1

eukaryotes regulate gene expression

Answer 1

for development and to maintain homeostasis

Question 2

gene expression 1. transcriptional regulation

Answer 2

transcriptional regulation depends on the ability of RNA polymerase to interact with the DNA and thus its ability to initiate transcription
-most common form of regulation of gene expression in both pro-and eukaryotic cells

Question 3

promoter region

Answer 3

regulatory DNA sequence upstream from transcription start site RNA polymerase binds to core promoter

Question 4

regulatory proteins

Answer 4

affects the ability of RNA polymerase to bind to the promoter or to initate transcription

Question 5

DNA components of operon regulation

Answer 5

core promoter region
activator binding site
operator

Question 6

core promoter region

Answer 6

bound by sigma factor of RNA polymerase

Question 7

activator binding site

Answer 7

-bound by positive control (activator) proteins
-may be close to the core promoter of further away

Question 8

operator

Answer 8

bound by negative control (repressor) proteins

Question 9

lac operon

Answer 9

-produces the proteins required for lactose metabolism
-lac repressor proteins inhibits transcription when lactose is absent
-CAP activator protein promotes transcription when glucose is absent

Question 10

trytophan produced by trp operon encoded proteins

Answer 10

-the trp repressor inhibits transcription when trytophan is available