Microbiology Chapter 8 Review

As a general rule, any given gene has only one type of control system.

False

Bacteria are the only microorganisms capable of regulating expression of their genes

False

Controlling the activity of an enzyme is an inefficient use of the organism's energy

False

DNA-binding proteins typically affect translation of a protein

False

During chemotaxis, attractants increase the rate of autophosphorylation whereas repellants decrease this rate

False

Histones are universally present in prokaryotic cells

False

In catabolic repression, cells use the least abundant carbon source first.

False

In most cases, the first product of a particular biosynthetic pathway represses the enzymes of the pathway

False

Regulation of the amount of enzyme synthesized occurs only at the gene level

False

Small molecules usually act directly (rather than indirectly) in regulating transcription

False

The major means of regulation in prokaryotes occurs posttranslationally

False

The regulation of enzyme synthesis is usually a more rapid process than the regulation of enzyme activity

False

When arginine is added to a culture growing exponentially in a medium without arginine, what occurs?

Growth continues, but the production of enzymes required for the synthesis of arginine ceases.

What occurs when an inducer is added to an environment containing an organism with a metabolic pathway controlled by a repressor

The inducer combines with the repressor and inactivates the pathway

In negative control of transcription, how does the presence of an inducer affect transcription

The inducer prevents the repressor from binding to the operator

Enzymes carry out the different biochemical reactions needed for cell growth

True

For the CRP protein to bind to the DNA in the promoter region and thus facilitate translation, a sufficiently high level of cyclic AMP must be present

True

In discussing the control of enzyme transcription, it is essential to consider the cell's environment

True

In the tryptophan operon, translation of the leader peptide regulates transcription of the tryptophan genes downstream and is called attenuation

True

Most DNA-binding proteins interact with DNA in a sequence-specific manner

True

Proteins and RNA molecules that are needed in the cell, at about the same level under all growth conditions, require constitutive expression

True

Proteins that bind to DNA can either block or activate transcription

True

The catabolism of the sugar maltose in Escherichia coli is an example of a system that involves positive regulation

True

The lactose operon and the maltose regulon are under the control of global control mechanisms as well as their own specific regulatory systems

True

Transcriptional regulation is considered negative when an inducer binds to and deactivates a repressor

True

When cells experience heat shock, the degradation of sigma factor 32 is inhibited

True

What is the direct cause of catabolite repression

a cellular deficiency of cyclic AMP

Endospore formation in Bacillus subtilis is triggered by adverse external conditions that are monitored by a five sensor kinase system whose mechanism resembles that of

a two-component regulatory system

Cyclic AMP is synthesized from ATP by an enzyme called

adenylate cyclase

Heat shock proteins perform which of the following functions

all of the above

Which of the following is a major phases of the regulation of differentiation in prokaryotes

all of the above

Which of the following is necessary for negative control of the tryptophan operon

all of the above

The most frequent way in which regulatory RNA molecules exert their effects is by

base pairing with other RNA molecules that have regions of complementary sequence

In enzyme induction, a(n) ________ represses enzyme production

corepressor

Regulatory proteins

do all of the above

When considering the biological information flow, transcription is usually thought of as the

first step

Alternative sigma factors in the cell regulate the

heat shock response

Protein binding occurs at the ________ site of DNA

major groove

Attenuation occurs in the biosynthetic pathway for phenylalanine in Escherichia coli. Therefore, the leader sequence for this pathway will be rich in which of the following

phenylalanine

The function of a kinase is

phosphorylation

Histones are ________, so they combine strongly and relatively nonspecifically with ________ DNA.

positively charged / negatively charged

Regulation of an enzyme's activity occurs

posttranslationally

Arginine in the culture medium

represses the synthesis of the enzymes required for the production of arginine

In the tryptophan operon, synthesis of the leader peptide results in

termination of transcription of the remainder of the trp operon

The promoters of positively controlled operons require activator proteins, because

the promoters have nucleotide sequences that bind RNA polymerase weakly, which are not close matches to the consensus sequence

Enzyme repression and induction occur at the level of

transcription

Enzyme induction occurs

when the substrate is present