Microbiology 1st Edition By Wessner – Test Bank

Package Title: Test Bank

Course Title: Wessner1e

Chapter Number: 11

Question Type: Multiple Choice

1) Expression of genes that are constitutive is:

1. a) regulated by repression.
2. b) unregulated.
3. c) regulated by induction.
4. d) regulated by activation.
5. e) regulated by attenuation.

Answer: b

Difficulty: Easy

Learning Objective: LO 11.1 Explain how inducible and constitutive genes differ and how the synthesis of gene products is regulated.

Section Reference: Section 11.1 How are enzymes controlled?

2) The expression of genes required for biofilm formation occurs only after a cell has attached to a surface that is suitable for biofilm development. What is this type of gene expression called?

1. a) attenuation
2. b) feedback inhibition
3. c) induction
4. d) repression
5. e) inhibition

Answer: c

Difficulty: Easy

Learning Objective: LO 11.1 Explain how inducible and constitutive genes differ and how the synthesis of gene products is regulated.

Section Reference: Section 11.1 How are enzymes controlled?

3) What is an effector molecule?

1. a) A protein that binds to an operator region of a gene.
2. b) An activator protein for gene expression.
3. c) A small RNA molecule that inhibits translation of mRNA.
4. d) A small molecule that binds to an enzyme to regulate its activity.
5. e) A small molecule that binds to the operator region of a gene.

Answer: d

Difficulty: Easy

Learning Objective: LO 11.1 Explain how inducible and constitutive genes differ and how the synthesis of gene products is regulated.

Section Reference: Section 11.1 How are enzymes controlled?

4) How is chemotaxis regulated?

1. a) By increased gene expression.
2. b) By decreased gene expression.
3. c) By a series of signal transduction events.
4. d) By allosteric enzymes.
5. e) By an induction-type mechanism.

Answer: c

Difficulty: Easy

Learning Objective: LO 11.2 Explain the role of operons in the positive or negative regulation of gene expression.

Section Reference: Section 11.2 How do regulatory proteins control transcription?

5) What is the function of methyl-accepting chemotaxis proteins (MCPs)?

1. a) To phosphorylate CheY.
2. b) To control the direction of flagellar rotation.
3. c) To dephosphorylate CheY.
4. d) To sense the presence of a specific chemical.
5. e) To drive the flagellum motors.

Answer: d

Difficulty: Medium

Learning Objective: LO 11.7 Describe the proteins involved in chemotaxis in bacteria and their functions.

Section Reference: Section 11.7 How can bacterial cells regulate their behavior?

6) What would characterize the phenotype of a CheY mutant?

1. a) Loss of motility.
2. b) Constant tumbling.
3. c) Smooth swimming.
4. d) Inability to sense certain chemicals.
5. e) Movement toward repellents and away from attractants.

Answer: c

Difficulty: Medium

Learning Objective: LO 11.7 Describe the proteins involved in chemotaxis in bacteria and their functions.

Section Reference: Section 11.7 How can bacterial cells regulate their behavior?

7) What would characterize the phenotype of a CheB mutant?

1. a) loss of motility.
2. b) constant tumbling.
3. c) smooth swimming.
4. d) inability to sense certain chemicals.
5. e) movement toward repellents and away from attractants.

Answer: b

Difficulty: Hard

Learning Objective: LO 11.7 Describe the proteins involved in chemotaxis in bacteria and their functions.

Section Reference: Section 11.7 How can bacterial cells regulate their behavior?

8) During negative regulation of gene expression the repressor protein binds to the operator to inhibit transcription. What is the effector molecule that controls the activity of the repressor protein called?

1. a) corepressor
2. b) inducer
3. c) activator
4. d) corepressor or inducer
5. e) corepressor or activator

Answer: d

Difficulty: Easy

Learning Objective: LO 11.2 Explain the role of operons in the positive or negative regulation of gene expression.

Section Reference: Section 11.2 How do regulatory proteins control transcription?

9) Which of these is required for transcription that is regulated by positive control?

1. a) activator protein
2. b) repressor protein
3. c) inducer protein
4. d) attenuator protein
5. e) DNA polymerase.

Answer: a

Difficulty: Easy

Learning Objective: LO 11.2 Explain the role of operons in the positive or negative regulation of gene expression.

Section Reference: Section 11.2 How do regulatory proteins control transcription?

10) Which of these controls the expression of the lac operon?

1. a) An activator protein only.
2. b) An attenuation mechanism.
3. c) A repressor protein only.
4. d) Both repression and activation mechanisms.
5. e) Both repression and attenuation mechanisms.

Answer: d

Difficulty: Easy

Learning Objective: LO 11.2 Explain the role of operons in the positive or negative regulation of gene expression.

Section Reference: Section 11.2 How do regulatory proteins control transcription?