Lac Operon

Question 1

What is the function of the Lac Operon?

Answer 1

It regulates the expression of genes

Question 2

The Lac Operon makes sure that

Answer 2

Only the proteins necessary are made

Question 3

The Lac Operon makes sure that gene expression is

Answer 3

Regulated at transcription

Question 4

The Lac Operon is found in

Answer 4

Bacterial E. Coli

Question 5

Bacterial E. Coli uses what as its main energy source?

Answer 5

Glucose

Question 6

What does Bacterial E. Coli use when glucose is not available?

Answer 6

Lactose

Question 7

The Lac Operon has genes which

Answer 7

Will help E. Coli break down lactose

Question 8

What are the three structural genes of the Lac Operon?

Answer 8

• Lac Z
• Lac Y
• Lac A

Question 9

Lac Z is a gene which

Answer 9

Breaks lactose into Glucose + Galactose and codes for Beta Galacto

Question 10

Lac Y is a gene which

Answer 10

Helps bring lactose into the cell and codes for Enzyme Lactose Permease

Question 11

The operator site is found where?

Answer 11

After the promoter site

Question 12

The operator site has which protein?

Answer 12

A repressor, which blocks RNA Pol by default

Question 13

When does the conformation of a Repressor change?

Answer 13

After lactose binds

Question 14

What happens to the repressor after the lactose binds?

Answer 14

The repressor falls off the operator site, allowing for the expression of the Lac Operon

Question 15

Lactose is composed of

Answer 15

Glucose + Galactose

Question 16

What is an Operon?

Answer 16

Unit of genomic DNA containing a cluster of genes which are controlled by a promoter

Question 17

What is a promoter?

Answer 17

A single regulatory signal

Question 18

Within the operon, a cluster of genes is transcribed into a

Answer 18

Single mRNA strand

Question 19

What is the Lac Operon?

Answer 19

Inducible set of genes responsible for importing and breaking down lactose as a use of energy

Question 20

What is the role of the Lactose in the Lac Operon?

Answer 20

It acts as an inducer, which induces the transcription of the Lac genes

Question 21

Which structural genes are needed for lactose catabolism?

Answer 21

• Lac Z

- Lac Y

Question 22

What is the function of the promoter of the Lac Operon?

Answer 22

It promotes transcriptional structural genes

Question 23

What are two regulatory sequences which lie upstream of Lac Operon?

Answer 23

• Repressor Protein Genes

- Associated promoter for that repressor protein

Question 24

The repressor protein is constitutively expressed when

Answer 24

Glucose is readily available to the cell

Question 25

What does the repressor protein do on a regular basis?

Answer 25

It represses binding of RNA Pol whenever glucose is readily available

Question 26

What happens when a regulatory protein binds to the lac operator?

Answer 26

It interferes with the operator and represses the binding of RNA Pol

Question 27

What is the goal of the RNA Pol regarding the operon?

Answer 27

To bind with the lac operator in the promoter region

Question 28

The binding of the regulatory protein allows for the

Answer 28

Prevention and repression of transcription of genes for lactose metabolism

Question 29

What happens when lactose is available to the cell and not glucose?

Answer 29

Lactose passively enters the cell at a slow rate

Question 30

What happens when the repressor falls off the operon?

Answer 30

RNA Pol is available to transcribe all 3 genes

Question 31

Lactose permease allows for

Answer 31

More lactose to enter the cell

Question 32

Beta Galact allows for the

Answer 32

Breaking down of lactose into galactose and glucose

Question 33

What is the “Inducer Exclusion”?

Answer 33

A process in which the transport of glucose blocks the transport of lactose into the lac operon

Question 34

The Lac Operon is the interaction between

Answer 34

The inducer and repressor molecules which mediate gene expression

Question 35

The cell expands energy to

Answer 35

Make enzymes only when necessary