Chapter 14

corepressor

A ... is a small molecule that binds to a repressor protein, thereby causing the protein to bind to DNA.

two

Allosteric proteins have at least ... binding sites.

inhibitor

An ... binds to an activator protein and prevent it from binding to the DNA.

operon

An ... is a group of two or more genes under the transcriptional control of a single promoter.

Polycistronic RNA

An RNA that contains the sequences for two or more genes.

Repressible

Both corepressors and inhibitors act to reduce the rate of transcription, therefore the genes they regulate are called ... genes.

lac operon

Contains a CAP site, promoter, operator, and three structural genes, and a terminator

Constitutive

Frequently ... genes encode proteins that are continuously needed for the survival of the bacterium.

allolactose

In the presence of ...., the lac repressor is bound to the operator site most of the time.

repressible

Operons that code for anabolic functions are typically .... (ex: trp operon)

inducible

Operons that code for catabolic functions are typically .... (ex: lac operon)

operator

The ... is a sequence of bases that provides a binding site for the repressor protein.

allosteric

The ... is a site other than the protein's active site.

Repressor

The lac operon is regulated by a .... protein.

negative

Transcriptional regulation by a repressor protein is termed ... control

cannot

When typtophan levels are very low, the trp repressor _____ (can/cannot) bind to the operator site.

repressor

a ... is a regulatory protein that binds to the DNA and inhibits transcription

inducible genes

genes that are regulated by inducers are called ...

DNA

genetic regulatory proteins that respond to small effector molecules have two functional domains. One domain is the site where the protein binds to the ...., the other is the binding site for the effector molecule.

allolactose binds to the lac repressor, causing a conformational change that allows transcription of lac genes to occur

lactose brought into cytoplasm via lactose permease beta-galactosidase converts it to allolactose allolactose levels in the cytoplasm gradually rise -what happens next?

False (this is how small effector molecules work)

true or false: regulatory proteins are given names that describe how they affect transcription when they are present in the cell at a sufficient concentration to exert their effect.

constitutive

unregulated genes are also called ...

Polycistronic

An operon encodes a ..., which is an RNA that contains the sequences for two or more genes.

promoter, terminator

An operon is flanked by a ... that signals the beginning of transcription, and a ... that specifies the end of transcription.

effector

In conjunction with regulatory proteins, small ... molecules often play a critical role in transcriptional regulation.

Allosteric regulation

The action of a small effector molecule on affecting the conformational shape of a protein is called ...

effector

The binding of the ... molecule causes a conformational change in the regulatory protein and thereby influences whether or not the protein can bind to the DNA.

trp repressor

The trpR gene encodes for the ... protein.

corepressor (binds to repressor that causes protein to bind to DNA), inhibitor (binds to activator protein and causes it to be unable to bind to DNA)

The two was a small effector molecule may INHIBIT transcription.

bind to repressor protein (prevent it from binding to DNA), bind to activator protein (causing it to bind to DNA)

The two ways that an inducer may work.

positive

Transcriptional regulation by an activator protein is considered to be ... control

True

True or false: regulatory proteins are given names describing how they affect transcription when they are bound to DNA.

True

True or false: when tryptophan levels are very low, the RNA polymerase transcribes the trp operon.

lactose permease

When a bacterium is exposed to lactose, a small amount can be transported into the cytoplasm via ...

corepressor

When the tryptophan levels within the cell become high, tryptophan acts as a ... that binds to the trp repressor protein.

activator

an ... is a regulatory protein that increases the rate of transcription

inducer

an ... is a small effector molecule that causes transcription to increase.

attenuation

-inhibits further production of tryptophan in the cell -used when operon is making trp -saves E and work -makes stem-loop and causes mRNA to have premature termination -secondary regulation method for anabolic system

beta-galactosidase

.... is encoded by a lac operon and functions to cleave lactose into galactose and glucose (also makes allolactose)

trp

The ... operon encodes enzymes that are needed for the biosynthesis of the amino acid tryptophan.

conformational change

When allolactose binds to the repressor, a .... occurs in the lac repressor protein that prevents it from binding to the operator site.