Course

Introductory Biology

Study Pack

Set 11 Gene Regulation

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Question 1

(Multiple Choice)

Free
a(n.________ operon is one whose transcription is decreased by effector molecules.

A)activated
B)repressible
C)inducible
D)coinducible
E)compressible

Answer

Question 2

(Multiple Choice)

Free
A bacteria contains two copies of the lac operon;one on the bacterial chromosome and one on a plasmid.The lacO site on the chromosomal lac operon is mutated and non-functional whereas the lacO site on the plasmid is functional.What is the most likely outcome for the bacterial cell when lactose is not available?

A)Expression of lac structural genes on the chromosome and plasmid will decrease because two copies of the lacO site are needed for repression of the lac operon.
B)Expression of lac structural genes on the plasmid,but not the chromosome,will increase because the mutation in the chromosomal lacO gene will prevent the expression of the genes.
C)Expression of lac structural genes on the chromosome but not the plasmid will increase because repressor proteins are unable to bind to the chromosomal lacO site,but are capable of binding the plasmid lacO site.
D)Expression of lac structural genes will not change because the lacO site is not a structural gene.

Answer

Question 3

(Multiple Choice)

Free
The lacA gene found within the lac operon encodes for galactosidase transacetylase.This enzyme attaches a(n)________ group to lactose and lactose analogs.

A)amino
B)hydroxyl
C)carbonyl
D)acetyl
E)carboxyl

Answer