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
