Microbiology Chapter 14

Match the following concerning types of genes.

- Constitutive genes: Genes that are continuously expressed - Regulated genes: Genes that are only expressed when needed.

Which two of the following are characteristics of the OmpR protein?

- DNA binding protein - Cytoplasmic protein

Match each bacterial group with their most common use of riboswitches.

- Gram-positive bacteria: Control of transcription - Gram-negative bacteria: Control of translation

Which two of the following are common motifs of the DNA-binding domains of regulatory proteins?

- Helix-turn-helix - Zinc fingers

Match each component of the E.coli chemotaxis response pathway with the correct function.

- MCP: Chemoreceptor - CheA: Sensor kinase - CheY: Response regulator

Which of the following are components of a bacterial operon?

- Operator - Structural genes - Promoter

A(n) __________ is a protein that is used to sense the presence of specific chemicals in the enviroment.

Chemoreceptor

E. coli detects the presence of specific molecular attractants with _________.

Chemoreceptors

Which characteristics best describes EnvZ?

Homodimeric; membrane-bound; sensor kinase

Enzymes that catalyze reactions that are in constant demand in a cell are encoded by genes referred to as __________ genes.

Housekeeping

Which of the following terms indicates that the binding of a protein to DNA inhibits the initiation of transcription?

Negative transcriptional control

Match each type of E. coli sigma factor with the conditions under which it is associated.

σ70: Normal conditions-exponential growth σF: Flagella and chemotaxis proteins needed σ60: Nitrogen metabolism σH: Heat shock stress

Identify the three statements about KinA activity in Bacillus subtillis that are true.

- Acts as a sensor kinase - Autophosphorylates a specific histidine residue - Sense nutrient starvation

Which two conditions must be met for AraC to act as a repressor of the ara operon?

- Arabinose must be absent - Two AraC proteins on different regulatory sequences must interact

Which two conditions must be met for AraC to act as an activator of the ara operon?

- Arabinose must be present - Two AraC proteins must bind to aral

Which two of the following are characteristics of transcriptional regulatory proteins?

- Bind to palindromes - Bind to DNA

Which two of the following statements about the inhibition of transcription by the lac repressor protein are true?

- Binds O1 and one additional lac operator site - Bends the DNA in the promoter region

Which three of the following are characteristics of the AraC protein?

- Can interact with three different regulatory sequences - Can act as a repressor - Can act as an activator

The transcription of all catabolite operons are regulated by which two of the following?

- Catabolite activator protein - Regulatory protein specific to the operon

Which three of the following are characteristics of the EnvZ protein?

- Homodimeric protein - Sensor kinase protein - Integral membrane protein

Which two of the following statements about the interaction between the lac repressor and inducer are true?

- Inducer binding changes the repressor shape. - Inducer binding causes repressor to lose ability to bind to the operator sites

Bacteria can regulate transcription at the levels of __________.

- Initiation - Elongation

Which three of the following characteristics of the EnvZ protein?

- Integral membrane protein - Sensor kinase protein - Homodimeric protein

Match each type of regulated gene with the correct statement about its regulatory protein.

- Negatively controlled inducible gene: Repressor protein is active; inactivated by an inducer - Positively regulated inducible gene: Activator protein is inactive; activated by an inducer

Which three of the following mechanisms are used by Bacillus subtilis to control sporulation?

- Post transitional modification - Alternate sigma factors - Phosphorelay

Which two of the following conditions are required for full activation of lac operon?

- Presence of lactose - Low levels or absence of glucose

DNA-bound repressor proteins inhibit the initiation of transcription by either __________.

- Preventing the movement of RNA polymerase - Blocking the binding of RNA polymerase

The two types of response regulators in two-component signal transduction systems are:

- Proteins that control enzymes - DNA-binding proteins

The two types of response regulators in two-components signal transduction systems are:

- Proteins that control enzymes - DNA-binding proteins

Match each regulatory process with the correct effect on transcription of the trp operon.

- Repression: 70 fold decrease - Attenuation: 8-10 fold decrease - Repression and attenuation: 600 fold decrease

Which of the following are component proteins of a two-component signal transduction system?

- Response regulator - Sensor kinase

Which two statements about bacterial flagellar movement are true?

- Run results from counterclockwise motion - Tumble results from clockwise motion

Flagellar movement in E. coli involves a combination of smooth swimming motions called _________, and nonspecific rotation called ________.

- Runs -Tumbles

The term used to describe the metabolic pathway that uses DNA as a template for the manufacture mRNA is called _________, and the pathway that uses mRNA as the template for the manufacture of protein is called _____________.

- Transcription - Translation

Which two of the following are characteristics of a sensory kinase?

- Transmembrane protein - Detects specific changes in the environment

Match each sigma factor with its correct timing and location during sporulation.

- σF: Early gene expression in forespore - σE: Early gene expression in mother cell - σG: Late gene expression in developing endospore - σK: Late gene expression in mother cell

Place the sequence of events of chemotaxis regulation of flagellar rotation direction in the correct order.

1) Attractant binds to methyl-accepting chemotaxis protein 2) CheA autophosphorylates 3) CheA transfers phosphoryl group to CheY 4) CheY interacts with flagellar motor

Initiation of sporulation in Bacillus subtilis involves a series of phosphorylation events. Place the below proteins into the order in which they are phosphorylated.

1) KinA 2) SpoOF 3) SpoOB 4) SpoOA

Place the steps of EnvZ/OmpR control of porin gene transcription in the correct order.

1) Osmolarity of environment increases 2) Envz autophosphorylates 3) OmpR is phosphorylated 4) OmpR binds to DNA 5) ompF transcription is repressed; ompC transcription enhanced

Place the steps of Envz/OmpR control of porin genes transcription in the correct order.

1) Osmolarity of environment increases 2) Envz autophosphorylates 3) OmpR is phosphorylated 4) OmpR binds to DNA 5) ompF transcription is repressed; ompC transcription enhanced

Rank the following regulatory processes on their negative effect on transcription of the trp operon, from greatest effect to least.

1) Repression and attenuation 2) Repression only 3) Attenuation only

In the promoter of ppGGpp-regulated genes there are ________ rich regions that form stable open complexes that are not destabilized by ppGGpp and DksA.

AT

When ________ proteins bind to their transcriptional regulatory sites they facilitate the binding of RNA polymerase.

Activator

Proteins that promote the initiation of transcription by binding to DNA are called ________.

Activator proteins

ATP is converted to cAMP by the enzyme _________ ________.

Adenal cyclase

The sugar _______ is the inducer of the lac operon.

Allolactose

The stringent response is induced when bacterial cells are starved for _______.

Amino acids

Pieces of RNA that complementary to mRNA are called __________.

Antisense RNA

What protein is responsible for binding the ara operon DNA in such a way to prevent RNA polymerase from binding to the ara promoter?

AraC

Termination of transcription elongation before RNA polymerase enters the first structural gene of an operon is called _________.

Attenuation

The AHL signaling molecule is termed a(n) _________ (AI) to reflect autoregulatory nature of the system.

Autoinducer

Which statement best describes the ara operon?

Both negative and positive transcriptional control

In E. coli regulatory pathways, which molecule functions to insure that glucose is used as the preferred carbon and energy source?

CAP

Which of the following is NOT a characteristic of the OmpR protein?

Can phosphorylate itself

Which of the following is most likely to contain inducible enzymes?

Catabolic pathways

In E. coli, the proteins necessary to utilize lactose as an energy and carbon source will not be expressed, even when lactose is present, unless the _______ ________ protein is activated by the absence of glucose in the cell.

Catabolite activator

The positive regulatory system called __________ _________ prevents the expression of genes encoding proteins necessary for the utilization of sugars other than glucose when adequate supplies of glucose are present.

Catabolite repression

_________ genes are genes that are continuously expressed.

Constitutive

In two-compnent signal transduction systems, the response regulators are usually _________ binding proteins, or sometimes proteins that control the activity of enzymes or other proteins of the global network.

DNA

In two-component signal transduction systems, the response regulators are usually __________ binding proteins, or sometimes proteins that control the activity of enzymes or other proteins of the global network.

DNA

A pattern of bacterial growth in two phases caused by the presence of two sugars in the media is called __________.

Diauxic growth

Which of the following is NOT a component of bacterial operons?

Enhancer

The zinc finger DNA-binding domain are most commonly observed in the regulatory proteins of the domain ______________.

Eukaryotes

Which of the following are encoded by the trp operon?

Five structural genes

Regulatory systems that simultaneously control the expression of multiple operons or pathways are referred to as ________ regulatory systems.

Global

A protein that activates or represses multiple operons or genes is referred to as a(n) ______.

Global regulatory proteins

Which of the following is NOT a characteristic of the lac repressor protein?

Has zinc finger DNA-binding domains

Most E. coli antisense RNAs regulate their target RNAs through interaction with a protein called

Hfq

The level of some enzymes, such as β-galactosidase, increase significantly in the presence of a small effector molecule called a(n) ___________.

Inducer

Small effector molecule whose presence increases the level of specific enzymes are called ________.

Inducers

________ genes encode enzymes whose level is increased by the presence of small effector molecules.

Inducible

Two-component signal transduction systems are composed of a sensor __________ protein and a response regulator protein.

Kinase

When is adenyl cyclase active?

Little or no glucose is available

Which statement best describes the lac operon in E. coli?

Negative transcriptional control of inducible genes (i.e., turned "off" until turned "on")

The trp operon is best described as an example of the

Negative transcriptional control of repressible genes

Bacterial repressor proteins bind to a DNA sequence called the _________.

Operator

In E. coli, the EnvZ/OmpR two-component signal transduction system controls ________.

Porin production

The increase in transcription of the luxI gene in response to increases in the cellular concentration of AHL is an example of ________ autoregulation.

Positive

__________ transcriptional control occurs when the initiation of transcription is promoted by the binding of a protein to DNA.

Positive

Autoinduction can also be called ___________ sensing

Quorum

_________ _________ is a process by which a population of bacteria can coordinate gene expression through the exchange of signaling molecules.

Quorum Sensing

Which of the following is NOT a mechanism by which bacteria regulate gene expression?

Regulation of mRNA processing

Proteins involved in the control of gene expression in processes such as induction and repression are referred to as _________.

Regulatory proteins

_______ genes encode enzymes that have their expression levels decreased by the presence of pathway products.

Repressible

The genes that encode enzymes that have their expression levels decrease in the presence of pathway end-products are best described as _________.

Repressible genes

A(n) _______ protein is a DNA-binding protein that inhibits the initiation of transcription.

Repressor

A specialized form of attenuation that involves alternate foldings of the leader sequence of mRNA, but not ribosome behavior, is called _________.

Riboswitch control

Sigma factor σF is encoded by the gene _________.

SigF

Global regulatory systems are NOT likely to involve the simultaneous regulation of ________.

Single operons

RNA molecules that do not function as mRNA, tRNA, or rRNA are referred to as ________ or noncoding RNAs.

Small

sRNAs are _________.

Small RNAs

In Bacillus subtilis, phosphorylated SpoOA activates the expression of genes necessary for _________.

Sporulation

The __________ response is observed in many bacteria that are starved for amino acids.

Stringent

Genes that encode the non-regulatory proteins in an operon are referred to as ________ genes.

Structural

The term "regulation of gene expression" refers to the process that controls _______.

Transcription and translation

The steps of gene expression, in the correct order, are ______.

Transcription, translation

True or false: All catabolite operons are regulated by CAP and a regulatory protein that is specific to each operon.

True

The interaction of cellular _______-di-GMP with specific effector proteins has been shown to influence the expression of genes associated with biofilm formation, virulence factor production, and motility.

c

AHL is synthesized by the enzyme AHL synthase which is encoded by the gene ___________.

luxI

Following the partitioning of the mother cell and the forespore, the first sigma factor to be found in the forespore is _______.

σE