Question 1

If a set of genes is induced in the presence of the controlling substance,it is referred to as __________ control.

Accepted Answer

positive

Question 2

Gene regulation during sporulation in Bacillus subtilis involves BOTH temporal and spatial control.

Accepted Answer

Gene regulation during sporulation in Bacillus subtilis involves both temporal control, where different genes are activated at specific stages of sporulation, and spatial control, where different genes are expressed in different regions of the developing spore.

Question 3

When there is no arabinose available in the environment,the AraC protein acts as a(n)______________ for the
E.coli ara operon.

Accepted Answer

rep ressor

Question 4

In the presence of both glucose and lactose,the lactose repressor is not bound to the operator and the genes of the lactose operon are expressed.

Accepted Answer

In the presence of both glucose and lactose, the lactose repressor can be inactivated by allolactose (a form of lactose), allowing the genes of the lactose operon to be potentially expressed. However, the presence of glucose activates a separate regulatory mechanism that suppresses the expression of these genes by preventing the accumulation of cAMP, which is necessary for the activation of the operon by CAP (catabolite activator protein). Thus, the full expression of the lactose operon in the presence of glucose is inhibited, even if the repressor is not bound to the operator.

Question 5

While standard two-component regulatory systems typically act to control gene transcription,phosphorelay systems can act either to control gene transcription or to control

Accepted Answer

Phosphorelay systems can activate or deactivate proteins and enzymes by adding or removing phosphate groups, which can lead to changes in their activity. This can include changes in protein function, localization, or stability, but does not directly affect transcription or DNA replication.

Question 6

The

Accepted Answer

The answer of The
...

Question 7

When arabinose is present in the environment,the AraC protein acts as a(n)______________ for the
E.coli ara operon.

Accepted Answer

The answer of When arabinose is present in the environment,the...

Question 8

So-called two-component regulatory systems

Accepted Answer

Two-component regulatory systems involve a sensor kinase and a response regulator, and they are crucial in various bacterial processes, including sporulation in Bacillus and regulation of porin proteins like OmpF and OmpC in E. coli.

Question 9

The sensor kinase for the OmpF: OmpC two-component regulatory system is

Accepted Answer

The sensor kinase for the OmpF: OmpC two-component regulatory system is the EnvZ protein. This has been extensively studied and shown to be responsible for sensing and responding to changes in osmolarity by phosphorylating the response regulator OmpR, which then regulates the expression of OmpF and OmpC porin genes. OmpK is a porin protein, and MicF is a small non-coding RNA that regulates porin gene expression but is not involved in the two-component regulatory system.

Question 10

In two component regulatory systems,the response regulator typically receives a ____________ from the sensor kinase when it has been activated.

Accepted Answer

In two component regulatory systems, the sensor kinase autophosphorylates with ATP, and then transfers the phosphoryl group to a conserved histidine residue. The activated sensor kinase then transfers the phosphoryl group to the response regulator, which can then bind to DNA and regulate gene expression.

Question 11

The real inducer for the
E.coli lac operon is allolactose produced by the action of permease on lactose.

Accepted Answer

Allolactose is produced by the action of β-galactosidase on lactose, not permease.

Question 12

Small RNAs that regulate translation by binding to the leader region of mRNAs are called antisense RNAs.

Accepted Answer

Antisense RNAs can bind to the leader region of mRNAs and regulate translation by blocking ribosome binding or inducing mRNA degradation.

Question 13

If a set of genes is repressed in the presence of the controlling substance,it is referred to as __________ control.

Accepted Answer

The answer of If a set of genes is repressed...

Question 14

One way to regulate gene expression is through the production of different sigma factors.These cause RNA polymerase to bind to different sets of promoters,thereby altering the pattern of gene expression.

Accepted Answer

Different sigma factors can direct RNA polymerase to bind to different promoters, thereby regulating gene expression.

Question 15

The binding of arabinose to the AraC protein allows it to form a loop in the DNA upstream of the ara operon promoter.

Accepted Answer

The answer of The binding of arabinose to the AraC...

Question 16

____________ is used to measure the amount of a chemoattractant encountered over time.

Accepted Answer

The answer of ____________ is used to measure the amount...

Question 17

A collection of genes or operons controlled by a common regulatory protein is called a(n)___________.

Accepted Answer

The answer of A collection of genes or operons controlled...

Question 18

Two-component signal transduction systems are found in the Bacteria,but not in Archaea.

Accepted Answer

This statement is false. Two-component signal transduction systems are also found in some Archaea.

Question 19

Regulation of gene expression serves to do all of the following except

Accepted Answer

Regulation of gene expression primarily involves controlling the synthesis of proteins, not adjusting the activity of proteins that already exist in the cell.

Question 20

In order for high level expression of the
E.coli lac operon to occur,a complex of catabolite activator protein and __________ must be bound to the DNA near the promoter.

Accepted Answer

The answer of In order for high level expression of...

Quiz 14: Regulation of Bacterial Cellular Processes