Chapter 7 Homework

In the EnvZ/OmpR system, OmpR regulates expression of:

• CheA and CheY

• LacI and MaIT

• OmpC and OmpF

• PhoR and PhoP

OmpC and OmpF

The general stress response associated with stationary phase is controlled by the alternative sigma factor:

• RpoS

• PhoR

• RpoH

• LacI

RpoS

Quorum sensing allows Bacteria and some Archaea to assess:

• ATP concentration

• ribosome size

• chromosome copy number

• population density

population density

A typical two-component regulatory system contains a:

• sensor kinase and response regulator

• repressor and ribosome

• DNA polymerase and ligase

• tRNA and aminoacyl-tRNA synthetase

sensor kinase and response regulator

EnvZ responds to changes in:

• light

• phosphate concentration

• temperature

• osmotic pressure

osmotic pressure

CRP binds DNA only after it has bound:

• tryptophan

• cAMP

• ppGpp

• allolactose

cAMP

When an effector binds an allosteric transcription factor, it can:

• cause translation to occur without mRNA

• convert the protein into DNA

• alter the protein’s conformation and its ability to bind DNA

• remove the promoter from the chromosome

alter the protein’s conformation and its ability to bind DNA

The inducer that regulates LacI in the lac operon is:

• maltose

• allolactose

• glucose

• cAMP

allolactose

Enzyme induction is typically the production of an enzyme in response to the presence of its:

• repressor

• substrate

• final product

• operator

substrate

Corepressors turn on transcription, whereas inducers turn it off.

False

Feedback inhibition shuts down a biosynthetic pathway when:

• the substrate binds the active site

• RNA polymerase binds the promoter

• the pathway runs out of end product

• the end product binds allosterically to an early enzyme

the end product binds allosterically to an early enzyme

Clockwise flagellar rotation is associated with tumbling

true

Catabolite repression ensures that E. coli uses which carbon source first when it is available?

• lactose

• any carbon maltose

• glucose

• maltose

glucose

Which quorum-sensing molecule was the first class of autoinducer and occurs in several gram-negative bacteria?

• allolactose

• acyl homoserine lactone (AHL)

• ppGpp

• cAMP

Acyl homoserine lactone (AHL)

RpoS is an alternative sigma factor involved in the general stress response

True

A repressor protein typically turns off expression by binding the:

• ribosome-binding site

• origin of replication

• operator region

• active site of an enzyme

operator region

Catabolite repression favors lactose utilization over glucose when both are present.

False

Phosphorylated CheY promotes:

• clockwise flagellar rotation and tumbling

• cessation of all flagellar rotation

• counterclockwise rotation and running

• transcription of the lac operon

clockwise flagellar rotation and tumbling

In the lac operon, LacI normally:

• binds the operator and blocks transcription

• phosphorylates RNA polymerase

• degrades allolactose

• binds the promoter and activates transcription

binds the operator and blocks transcription

bacterial and archaeal genes can be arranged in operons controlled by a single protomer region.

True