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Worksheets

Operon

Total questions: 20

Worksheet time: 15mins

Name
Class
Date
1.
A protein that binds to the operator and blocks the RNA polymerase
a)
regulator
b)
repressor
c)
activator
d)
corepressor
2.
The "on/off" switch for an operon is called the
a)
promoter
b)
repressor
c)
operator
d)
gene
3.
What is the name of the stretch of DNA where RNA polymerase binds?
a)
operator
b)
promoter
c)
enhancer
d)
origin
4.
The lac operon genes only become expressed if:
a)
lactose binds to the repressor
b)
glucose binds to the repressor
c)
lactose binds to the operator
d)
the repressor binds to the operator
5.

What type of operon is the trp (tryptophan) operon?

a)

inducible

b)

repressible

c)

positive control

d)

promoible

6.

In the lac operon the inducer is

a)

allolactose

b)

glucose

c)

galactose

d)

all of the above

7.

What is 1 in the diagram?

a)

RNA polymerase

b)

Inducer

c)

Repressor

d)

Operator

8.

What is 2 in the diagram?

a)

RNA polymerase

b)

Inducer

c)

Repressor

d)

Operator

9.

What is 4 in the diagram?

a)

RNA polymerase

b)

Inducer

c)

Repressor

d)

Operator

10.

What is 5 in the diagram?

a)

RNA polymerase

b)

Inducer

c)

Repressor

d)

Operator

11.

In the bottom picture the operon is

a)

on

b)

off

12.

Which of the following is not a structural gene?

a)

lac z

b)

lac y

c)

lac a

d)

lac I

13.

The tryptophan operon is

a)

permanently turned on.

b)

turned on when tryptophan is present in the growth medium.

c)

turned off only when glucose is present in the growth medium.

d)

turned off when tryptophan is added to the growth medium.

14.

What does a promoter do?

a)

it allows a gene to be transcribed

b)

it creates a DNA segment

c)

it is another word for ribosomes

d)

it is another word for RNA

15.

Ara operon will be turned off once the araC binds to the operator of the _________ and binds to___________

a)

araO2 , araI

b)

araC , araB

c)

araO1, araO2

d)

araA, araD

16.

Structural genes of ara operon are

a)

ara D,A,B

b)

ara B,A,D

c)

ara Z,Y,A

d)

ara E,D,C,B,A

17.

In attenuation, the operon will stop once sequence _________and _________ basepair

a)

1,2

b)

2,3

c)

3,4

d)

1,3

18.

Trp operon is an example of operon that operates ___________

a)

ababolically

b)

catabolically

19.

Structural genes of trp operon encodes for

a)

tryptophan synthetase

b)

tryptophan dioxygenase

c)

tryptophan kinase

d)

tryptophan polymerase

20.

All these condition causes ara operon to turn on EXCEPT

a)

arabinose is bind to araC activator protein

b)

arabinose is present

c)

cAP-cAMP is present

d)

loop is formed