Genetics Smartbook Notes
prevents the cell from wasting energy
A benefit of gene regulation is that encoded proteins are not made when they are not needed. This
prevents repressor from binding to DNA
Allolactose is a small effector molecule that binds to the lac repressor and
increase
An induced is a small effector molecule that causes transcription to _______
repressor; activator
An inducer could bind to a(n) ______ and prevent it from binding to the DNA, or it could bind to a(n) ______ and cause it to bind to the DNA
polycistronic
An operon encodes a(n) ________ mRNA, an RNA that contains the sequences of two or more genes.
A single promoter
An operon is a group of at least two genes under the transcriptional control of
CAP site
Catabolite activator protein binding site
only when confronted with stress
Certain proteins help bacterium survive environmental stress such as heat shock. These proteins are required
all the time
Constitutive genes encode proteins the cell needs
metabolism
Control of gene expression leads to the production of specific proteins to assist bacterial cells in responses to environmental stressors, preparation for cell division, and
environmental
Examples of a(n) _________ stress that might equine a bacterium to produce a specific protein include osmotic shock or heat shock.
Producing enzymes to metabolize specific sugars when those sugars are found in the environment, when bacterial cells are getting ready to divide, and when bacteria are subject to heat stress
Genetic control of the production of specific proteins at specific times would occur in which of the following situations
A corepressor binds to a repressor protein, while an inhibitor binds to an activator protein.
How do a corepressor and an inhibitor differ?
promoter
In an operon, the _______ signals the beginning of transcription
Lactose
Monod and Jacob studied _______ metabolism in E. coli
True
T/F: A benefit of gene regulation is that encoded proteins will not be produced when they are not needed.
False
T/F: Gene regulation is constant
False
T/F: effector molecules influence gene expression by binding to DNA
short DNA segments
The CAP site and the operator site are ______ that function in gene regulation.
positive
Transcription regulation by an activator protein is considered to be ________ control
constitutive
Unregulated genes are also called ______ genes
constant levels of expression
Unregulated genes have
constitutive genes
What type of genes encode proteins the bacterial cell needs all the time?
alters the protein's ability to bind to DNA
When a small effector molecule binds to a regulatory molecule, it alters the regulatory protein's conformation, and that________
They are unregulated
Which is true about constitutive genes?
by binding to a repressor or activator
How does an effector molecule influence gene expression?
lacI
The ______ gene encodes a repressor protein
operon
A group of two or more genes under the transcriptional control of a single promoter is termed a(n)
two or more genes
A polycistronic mRNA contains the sequence(s) of
negative
A protein such as a repressor that inhibits transcription is exerting _______ control of transcription
repressor
A regulatory protein that binds to DNA and inhibits transcription is known as a
activator
A regulatory protein that increases the rate of transcription is a(n)
promoter
In an operon, the _________ signals the beginning of transcription.
the rate of transcription initiation
In bacteria, the most common way to regulate gene expression is by influencing
conformation
The binding of a small effector molecule to a regulatory protein changes the ______ of the regulatory protein, which alters the DNA-binding ability
Glucose and galactose
The enzyme beta-galactosidase cleaves the sugar lactose into
lactose
The exposure of bacterial cells to ______ increases the levels of lactose- utilizing enzymes 100- to 10000- fold
Blocks transcription
The lac repressor protein binds to the operator and _______
permease
The lacY gene encodes lactose _________, a membrane protein
promoter; terminator
The operon is flanked by a(n) ______ that signals the beginning of transcription and a(n) _______ that signals the end of transcription
gene regulation
The phenomenon in which the level of gene expression can vary under different conditions is
The transport of lactose into the bacterial cell
The product of the lacY gene is required for
lactose
The products of the lacA gene is galactoside transacetylase, an enzyme that covalently modifies
our initial understanding of gene regulation
The research of Jacob and Monod provided
enzyme adaptation
The research of Monod and Jacob that led to the initial understanding of gene regulation stemmed from an interest in ________
A,Y,Z
The three protein-coding genes in the lac operon are
Cannot transcribe
When the lac repressor is bound to the operator, RNA polymerase ___________ the lacZ, lacY, or lacA
allolactose
A conformational change that prevents the lac repressor from binding to the lac operator occurs when ________ binds to the lac repressor
activator
A regulatory protein that increases the rate of transcription is a(n) ________ gene
transcribes the operon
When four molecules of allolactose are bound to the lac repressor, the lac operon is induced, and RNA polymerase