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Unit 6 - Trp and Lac Operon

Total questions: 17

Worksheet time: 12mins

Name
Class
Date
1.

In the lac operon the inducer is

a)

allolactose

b)

glucose

c)

galactose

d)

all of the above

2.
A protein that binds to the operator and blocks the RNA polymerase
a)
regulator
b)
repressor
c)
activator
d)
corepressor
3.

In the lac operon the inducer is

a)

allolactose

b)

glucose

c)

galactose

d)

all of the above

4.

What is 1 in the diagram?

a)

RNA polymerase

b)

Inducer

c)

Repressor

d)

Operator

5.

What is 4 in the diagram?

a)

RNA polymerase

b)

Inducer

c)

Repressor

d)

Operator

6.
What is the name of the binding site of RNA polymerase in eukaryotes?
a)
operator
b)
operon
c)
inducer
d)
promoter
7.
What is the role of operons in prokaryote gene expression?
a)
It makes the genes prokaryotes be turned on
b)
It accounts for the regulation of gene activity in response to the needs of the cells
c)
To make DNA for the gene
d)
To make the gene turn of and off
8.
What type of operon is the trp (tryptophan) operon?
a)
inducible
b)
repressible
c)
positive control
d)
promoible
9.

In the trp operon, __ acts as a __ and helps the repressor bind to the operator.

a)

tryptophan, corepressor

b)

tryptophan, inducer

c)

lactose, corepressor

d)

lactose, inducer

10.

Match the following genetic regions to their roles:

a)

Makes a repressor protein

1.

Regulatory gene

b)

Place where transcription begins

2.

Promotor

c)

The on/off switch where the repressor protein binds

3.

Operator

d)

Codes for the main protein / enzymes

4.

Genes of Operon

11.

The lac operon is an example of an inducible operon. Which of the following describes the process that occurs when lactose is present?

a)

The lactose binds to the repressor which inactivates it and the repressor binds to the operator to turn translation on.

b)

The lactose binds to the repressor which activates it and the repressor releases from the operator to turn translation on.

c)

The lactose binds to the repressor which inactivates it and the repressor releases from the operator to turn translation on.

d)

The lactose binds to the repressor which activates it and the repressor binds to the operator to turn translation on.

12.

What is 5 in the diagram?

a)

RNA polymerase

b)

Inducer

c)

Repressor

d)

Operator

13.

What is 2 in the diagram?

a)

RNA polymerase

b)

Inducer

c)

Repressor

d)

Operator

14.

The trp operon is an example of a repressible operon. Which of the following describes the process that occurs when tryptophan is present?

a)

The tryptophan binds to the repressor which inactivates it and the repressor binds to the operator to turn translation off.

b)

The tryptophan binds to the repressor which activates it and the repressor releases from the operator to turn translation off.

c)

The tryptophan binds to the repressor which inactivates it and the repressor releases from the operator to turn translation off.

d)

The tryptophan binds to the repressor which activates it and the repressor binds to the operator to turn translation off.

15.

What is the primary function of the lac operon in E. coli?

a)

To break down lactose into glucose and galactose

b)

To synthesize lactose from glucose

c)

To repress the synthesis of lactose

d)

To enhance the uptake of glucose

16.

The operon model was discovered in E. Coli and is almost exclusively found in ​ (a)   .

Choose from the below words
prokaryotes
eukaryotes
17.
What is the role of operons in prokaryote gene expression?
a)
It makes the genes prokaryotes be turned on
b)
It accounts for the regulation of gene activity in response to the needs of the cells
c)
To make DNA for the gene
d)
To make the gene turn of and off