Chapter 14 - Bacterial Gene Regulation

Question 1

The level of gene expression can vary under different conditions

Answer 1

Gene regulation

Question 2

Genes that are unregulated

Answer 2

Constitutive

Question 3

What cellular processes are gene regulation important for?

Answer 3

1. Metabolism
2. Response to environmental stress
3. Cell division

Question 4

Where/when can gene regulation occur?

Answer 4

Any of the points on the pathway to gene expression

Question 5

Where does gene regulation occur during transcription?

Answer 5

On the gene

Question 6

What happens when you regulate gene expression during transcription?

Answer 6

Genetic regulatory proteins bind to the DNA and control the rate of transcription

Question 7

Where does gene regulation occur during translation?

Answer 7

mRNA

Question 8

What happens when you regulate gene expression during translation?

Answer 8

1. Translation repressor proteins can bind to the mRNA and prevent translation from starting
2. Antisense RNA can bind to the mRNA and prevent translation from starting

Question 9

Where does gene regulation occur during post-translation

Answer 9

1. Protein
2. Functional Protein

Question 10

What happens when you regulate gene expression during post-translation (in a protein)?

Answer 10

1. In feedback inhibition, the product of a metabolic pathway inhibits the first enzyme in the pathway
2. Covalent modifications to the structure of a protein can alter its function

Question 11

Transcriptional regulation involves the actions of what two main types of regulatory proteins?

Answer 11

Repressors and Activators

Question 12

What binds to DNA and inhibits transcription?

Answer 12

Repressors

Question 13

What binds to DNA and increases transcription?

Answer 13

Activators

Question 14

What refers to transcriptional regulation by repressor proteins?

Answer 14

Negative Control

Question 15

What refers to regulation by activator proteins?

Answer 15

Positive Control

Question 16

The presence of a small effector molecule may ___ transcription

Answer 16

Increase

Question 17

What are small effector molecules called?

Answer 17

Inducers

Question 18

What are genes called that can be regulated with Inducers?

Answer 18

Inducible

Question 19

In other cases, the presence of a small effector molecule may ___ transcription

Answer 19

Inhibit

Question 20

What binds to repressors and cause them to bind to DNA?

Answer 20

Corepressors

Question 21

What bind to activators and prevent them from binding to DNA?

Answer 21

Inhibitors

Question 22

What type of Inducible Gene?
1. In the absence of the inducer, this repressor protein blocks transcription
2. The presence of the inducer causes conformational change that inhibits the ability of the repressor protein to bind to the DNA
3. Transcription proceeds

Answer 22

Repressor Protein, Inducer Molecule, Inducible Gene

Question 23

What type of Inducible Gene?
1. This activator protein cannot bind to the DNA unless an inducer is present
2. When the inducer is bound to the activator protein, this enables the activator protein to bind to the DNA and activates transcription

Answer 23

Activator Protein, Inducer Molecule, Inducible Gene

Question 24

What type of Repressible Gene?
1. In the absence of a corepressor, this repressor protein will not bind to the DNA
2. Therefore, transcription can occur
3. When the corepressor is bound to the repressor protein, this causes a conformational change that allows the protein to bind to the DNA and inhibit transcription

Answer 24

Repressor Protein, Corepressor Molecule, Repressible Gene

Question 25

What type of Repressible Gene? 1. This activator protein will bind to the DNA without the aid of an effector molecule 2. The presence of an inhibitor causes a conformational change that releases the activator protein from the DNA 3. This inhibits transcription

Answer 25

Activator protein, Inhibitor Molecule, Repressible Gene

Question 26

What is a regulatory unit consisting of a few structural genes under the controlled by one promoter?

Answer 26

An operon

Question 27

An operon encodes a ___ that contains the coding sequence for tow or more structural genes

Answer 27

Polycistronic mRNA

Question 28

What important DNA sequences does an operon contain?

Answer 28

1. Promoter 2. Terminator 3. Structural Genes 4. Operator

Question 29

Who identified the lac operon?

Answer 29

Francois Jacob and Jaques Manod

Question 30

What are the two parts of the lac operon?

Answer 30

1. Regulatory Elements (Promoter, Operator, CAP Site) 2. Structural Genes (lacZ, lacY, lacA)

Question 31

What are the parts of the Regulatory Elements?

Answer 31

Promoter, Operator, CAP site

Question 32

What are the parts of the Structural Genes?

Answer 32

lacZ, lacY, lacA

Question 33

What binds RNA polymerase?

Answer 33

Promoter

Question 34

What binds the lac repressor protein?

Answer 34

Operator

Question 35

What binds the Catabolite Activator Protein (CAP)?

Answer 35

CAP site

Question 36

What encodes β-galactosidase and enzymatically cleaves lactose?

Answer 36

lacZ

Question 37

What encodes lactose permease and requires membrane protein for transport of lactose?

Answer 37

lacY

Question 38

What encodes galactoside transacetylase and covalently modifies lactose?

Answer 38

lacA

Question 39

What is unique about lacI?

Answer 39

1. It is not considered part of the lac operon? 2. It has its own promoter (the lacI promoter) 3. Constitutively expressed at fairly low levels 4. Encodes the lac repressor 5. Only a small amount of protein is needed to repress the lac operon

Question 40

How can the lac operon be transcriptionally regulated?

Answer 40

1. By a repressor protein 2. By an activator protein

Question 41

The binding of which inducer causes conformational change that prevents the lac repressor from binding to the operator site?

Answer 41

Allolactose

Question 42

What is the activator protein that can transcriptionally regulate the lac operon?

Answer 42

Catabolite Repression

Question 43

What happens when Catabolite Repression is exposed to both lactose and glucose?

Answer 43

1. E. coli uses glucose first, and catabolite repression prevents the use of lactose 2. When glucose is depleted, catabolite repression is alleviated, and the lac operon is expressed

Question 44

What is the sequential use of two sugars by a bacterium?

Answer 44

Diauxic Growth