Prokaryotic Gene Regulation

Question 1

The ___ is the prokaryotic mechanism for controlling gene expression

Answer 1

Operon

Question 2

Operons may be___. The default situation is off, and the sequence of events turns it on

Answer 2

Inducible

Question 3

Inducible operons produce ____ enzymes

Answer 3

Catabolic

Question 4

Operons may be ___. The default situation is on, and the correct sequence of events turns it off.

Answer 4

Repressible

Question 5

Reprensible operons produce ____ enzymes

Answer 5

Anabolic

Question 6

Lactose is composed of ___+____

Answer 6

Glucose+galactose

Question 7

The major goal of the ___ is to produce glucose

Answer 7

Lac operon

Question 8

The mechanism by which glucose influences the function of the Lac operon

Answer 8

Catabolite Repression

Question 9

High levels of glucose inactive the enzyme ___

Answer 9

Adenylate cyclase

Question 10

Without adenylate cyclase, cells do not produce ___

Answer 10

cAMP

Question 11

Second messenger, derived from ATP, essential for many cellular processes

Answer 11

Cyclic Adenosine Monophosphate (cAMP)

Question 12

cAMP is a ___ in the Lac operon

Answer 12

Positive Regulator

Question 13

cAMP attaches to a protein called the ___

Answer 13

Catabolite Activator Protein

Question 14

The cAMP-CAP complex attaches to the promoter region of the ___. When attached to the promoter, cAMP-CAP enhances transcription of the three structural genes (z,y,a).

Answer 14

Lac operon

Question 15

Cells with a large glucose supply ___ break down lactose

Answer 15

Do not

Question 16

In cells with both glucose and lactose, ___ determines gene expression

Answer 16

Glucose

Question 17

Regulatory gene makes an ___ repressor molecule

Answer 17

Immature/inactive

Question 18

___ serves as a co-repressor. It attaches to app-repressor and induces conformational change

Answer 18

Tryptophan

Question 19

___ attaches to the operator, blocking structural gene transcription

Answer 19

Repressor-tryptophan complex

Question 20

When ___ is present, the operon is off

Answer 20

Tryptophan

Question 21

In ___ there is a high degree of sensitivity to the presence/absence of the molecule made by the anabolic enzymes

Answer 21

Reprensible Operons

Question 22

The sensitivity is based on usage of the gene segment called the ___.

Answer 22

Leader sequence

Question 23

The ___ is found within that leader sequence

Answer 23

Attenuator Region

Question 24

Leader region is completely translated, allowing loop 1-2 and 3-4 to form. The formation of this stem and loop results in the termination of transcription

Answer 24

High Tryptophan Level

Question 25

Ribosome is stalled at trp codons. Ribosome is waiting for tRNA to translate, which causes RNA polymerase t o pause, loop 2-3 forms, preventing 1-2 and 3-4 formation, allowing transcription to continue

Answer 25

Low tryptophan level