Ch.16 Gene Regulation in Bacteria Practice
What protein binds to each site? 1. Catabolite Activator Protein 2. Repressor 3. RNA polymerase
1. CAP Site 2. Operator 3. Promoter
How do a corepressor and an inhibitor differ?
A corepressor binds to a repressor protein, while an inhibitor binds to an activator protein.
(3) Processes that are regulated at the genetic level?
Metabolism Response to Environment Cell Division
What type of regulation does not need to be adjacent to the gene it is regulating?
Trans-acting factor
An operon is a group of two or more genes under the transcriptional control of________
a single promoter.
A regulatory protein that increases the rate of transcription is a(n)____________
activator
The observation that a particular enzyme appear within a cell only after the cell has been exposed to the enzyme's substrate is called enzyme__________.
adaptation
A conformational change that prevents the repressor from binding to the lac operator occur when______ binds to the lac repressor.
allolactose
The intracellular concentration of the inducer _________ remains high as long as lactose is available in the environment.
allolactose
A regulator site on a protein where an effector molecule binds is called a(n)__________ site.
allosteric
An enzyme may contain two sites: a catalytic site, and a regulatory or __________ site.
allosteric
Cyclic-AMP is a small effector molecule produced by the enzyme
andeylyl cyclase
Transcription begins but terminates before the entire mRNA is made during _________.
attenuation
The term that describes how transcriptional regulation is influenced by glucose is ______ _______.
catabolite repression
In catabolite repression, transcription is influenced by the presence of _____________.
glucose
The transport of ________ into a cell causes a _____ in the concentration of cyclic-AMP by inhibiting adenylate cyclase.
glucose; decrease
An inducer is a small effector molecule that causes transcription to ______
increase
In feedback inhibition, the final product in a metabolic pathway________________
inhibits an enzyme that acts early in the pathway.
During attenuation, transcription begins but _____________________________________________.
is terminated before the entire mRNA is made.
All of the protein-encoding genes in the lac operon:
lacA ,lacY ,lacZ
The _____ gene encodes a repressor protein.
lacI
A translational repressor protein binds to _________________
mRNA near the start codon.
A strain of bacteria containing F' factor genes is called a __________ or partial diploid.
merozygote
A protein such as a repressor that inhibits transcription is exerting ________ control of transcription.
negative
Certain proteins help a bacterium survive environmental stress such as heat shock. These proteins are required__________
only when confronted with the stress.
The lacY gene encodes lactose _________, a membrane protein.
permease
Constitutive genes encode
proteins the cell needs all the time.
The process of which the level of gene expression can vary under different conditions is gene _____________.
regulation.
Anabolic enzymes are usually encoded by ____ operons, and _____ operons usually encode catabolic enzymes.
repressible, inducible
A corepressor is a small molecule that binds to ___________ protein, thereby causing the protein to bind to the DNA, while an inhibitor binds to an ________________ protein and prevents it fro binding to the DNA.
repressor; activator
A translational repressor protein may bind to the mRNA and __________
stabilize a secondary structure that prevents translation.
In bacteria the most common way to regulate gene expression is by influencing__________
the rate of transcription initiation.
The trp operon is regulated by a repressor protein and by _______ in which transcription is stopped prematurely.
attenuation
A polycistronic mRNA
contains the sequences of two or more genes.
Posttranslational regulation refers to
control of proteins already in the cell.
The product of an operon may act as a(n) _______ if the operon is repressible.
corepressor
Examples of a(n)________ stress that might require bacterium to produce a specific protein include osmotic shock or heat shock.
enviromental
A DNA segment that must be adjacent to the genes it regulates is a _____________ element.
cis-acting
Constitutive genes are
unregulated
All of the genes in the trp operon:
trpA, trpB, trpC, trpD, trpE