Ch 14 Gene Regulation in bacteria Ch 15 Gene regulation in Eukaryotes I: Transcriptional and Translational Regulation

Unregulated genes are also called _______________ genes

constitutive

The enzyme beta-__________________ cleaves the sugar lactose into ______________ and ______________.

galactosidase; galactose; glucose

the lacA gene encodes the enzyme _______________ ______________.

galactoside transacetylase

An operon is a group of two or more genes under the transcriptional control of _______________.

single promoter

Determine if it describes regulation at the transcription, translation or post-translation level. Riboswitches produce an RNA conformation that prevents ribosome binding.

translation

The product of the lacY gene is required for the _______________ of _____________ into the bacterial cell.

transport; lactose

T/F: A transcription factor can have multiple domains.

true

T/F: Estrogen is a gonadocorticoid.

true

T/F: Glcocorticoid receptors have a nuclear localization signal that is hidden until a glucocorticoid is bound.

true

T/F: Glucocorticoid response elements function as enhancers.

true

T/F: In the absence of glucose and presence of lactose, allolactose combines with the repressor and allows RNA polymerase to proceed with transcription.

true

T/F: Polycistronic mRNA is transcribed from the lac operon when lactose is present in the cell.

true

T/F: The function of regulatory transcription factors is modulated.

true

T/F: The lac repressor does not completely inhibit transcription of the lacZ, lacY, and lacA genes.

true

T/F: The lac repressor protein is active in the absence of lactose within the cell.

true

T/F: The lacI gene makes a repressor protein.

true

T/F: The product of lacI is an allosteric protein that can undergo a conformational change when allolactose binds it.

true

T/F: Two glucocorticoid receptors function as a homodimer.

true

A polycistronic mRNA contains the sequences of _____________ genes.

two or more

Leucine _____________ motifs mediate dimerization between two ________________.

zipper; protein

Transcription of the lac operon results in the production of how many different mRNA transcripts?

1

Exposure of bacterial cells to lactose increases levels of lactose-utilizing enzymes ___________ (#) fold.

1000-10000

You are studying a bidirectional enhancer with the sequence 5'-CCTA-3'. Regulatory transcription factors that bind this sequence should also bind ______.

3'-ATCC-5'

When ______(#) molecules of _______________ are bound to lac repressor, and repressor can no longer bind to operator, and RNA polymerase is free to transcribe the operon, the operon has been ___________.

4; allolactose; induced

B-galactosidase activity can be detected using the lactose analog B- ___________ because B-galactosidase cleaves it to a product of yellow color.

ONPG

General transcription factors are required for the binding of ______ __________ to the core promoter and its progression to the elongation stage.

RNA polymerase

Monod, Jacob, and Pardee identified rare E.coli mutatns that had __________________________.

abnormal lactose adaptations

Monod, Jacob, and Pardee studied an E. coli strain with a lacI- mutation in which the lac operon was expressed even in the ____________ of ______________. Multiple choice question.

absence; lactose

An _______________ is a regulatory protein that binds to DNA and increases the rate of transcription.

activator

Cyclic-AMP is a small effector molecule produced by the enzyme ___________ ______________.

adenyl cyclase

______________ is a small effector molecule that binds to the lac repressor and prevents the repressor from binding to __________.

allolactose; DNA

The intracellular concentration of the inducer ____________ remains high as long as ___________ is available in the environment.

allolactose; lactose

Allolactose molecules bind to regulatory sites on the lac repressor protein called ____________ sites that differ from the region of the repressor that binds the operator.

allosteric

The binding of the allolactose inducer to the lac repressor occurs at a(n) ______ site.

allosteric

In helix-turn-helix and helix-loop-helix motifs ______________ __________ side chains of the a-helix form ___________ bonds with nucleotides.

amino acids; hydrogen

A regulatory element that functions in the forward or reverse direction is said to be _____________________.

bidirectional

When the lac repressor is bound to the operator, RNA polymerase ________________ transcribe the lacZ, lacY, or lacA genes.

cannot

The somewhat imprecise term that describes how transcriptional regulation is influenced by glucose is ____________ _____________.

catabolite repression

_______________ genes encode proteins the bacterial cell needs all the time.

consitutive

Unregulated genes have _____________ levels of expression.

constant

DNA sequences that are analogous to the operator sites found near bacterial promoters are called _________________ elements or _____________ sequences.

control; regulatory

In general, transcriptional regulation is aimed at _____________ the initiation of transcription at the _______________.

controlling; promoter

The CAP site and the operator site are short _______ ____________. that function in gene regulation.

dna segments

The binding of a regulatory transcription factor to an ______________ can stimulate 10-1000 fold, which is called _______ regulation.

enhancer; up

Activators bind to __________________.

enhancers

T/F: CAP binding causes the DNA to bend facilitating RNA polymerase binding.

false

T/F: Effector molecules influence gene expression by binding to DNA.

false

T/F: Gene regulation is constant.

false

T/F: Glucocorticoid receptors are membrane bound.

false

T/F: Glucocorticoid receptors bind to GRE elements which are present on newly synthesized mRNAs.

false

T/F: Steroid hormones are synthesized in the same cells where they function.

false

T/F: The CAP protein is an activator that binds to the operator.

false

T/F: The rate of transcription initiation rarely influences overall gene expression.

false

T/F: The structural proteins encoded by the lac operon are involved in lactose synthesis.

false

The transport of _____________ into a cell causes a _____________ in the concentration of cyclic-AMP by inhibiting ___________ __________.

glucose; decrease; adenyl cyclase

A domain called an a-_____________ is often found in transcription factors because it is the proper width to fit into the _____________ groove of the DNA double helix.

helix; major

The dimerization of two different proteins leads to a _________________.

heterodimer

The dimerization of two identical proteins results in a _____________.

homodimer

An inducer is a small effector molecule that causes transcription to ____________.

increase

lac operon regulation is ________________ and under ____________ & ___________ control.

inducible; negative; positive

When bound to operator, the lac repressor allows very small amounts of the ______ _______ to be made.

lac enzyme

When the levels of allolactose rises in an E.coli cell, allolactose binds to the _____ ______________ and prevents it from binding to the operator.

lac repressor

The ________ gene encodes a repressor protein.

lacI

The enzyme β-galactosidase is encoded by which gene?

lacZ

If the cell has a mutation in the lacY gene, then the lac operon cannot be induced because _____________ cannot enter the cell.

lactose

Monod and Jacob studied _______________ metabolism in E. coli.

lactose

The lacA gene encodes galactoside transacetylase, an enzyme that covalently modifies ______.

lactose

When only ___________ is present, allolactose and cAMP levels are high.

lactose

The absence of ____________ results in the lac repressor protein binding to ___________.

lactose; DNA

______ glucose and ___________ lactose results in high levels of gene transcription from the lac operon.

low; high

What is the name for a strain of bacteria containing an F' factor?

merozygote

A _____________ is a domain that has very similar structure in many different ________________.

motif; proteins

A protein such as a repressor that inhibits transcription is exerting ___________ control of transcription.

negative

When the lac repressor binds to the lac _______________, site, RNA polymerase cannot transcribe the lacZ, lacY or lacA genes.

operator

The lac repressor protein binds to the ______________ and blocks ______________.

operator; transcription

The lac repressor binds to the ______________ and prevents ______________ of the ______________ _______________.

operator; transcription; lactose operon

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

operon

the lacY gene encodes lactose _____________, a membrane protein.

permease

The function of a regulatory transcription factor can be modulated by covalent modifications, such as the attachment of a ________________ group.

phosphate

An operon encodes a ____________ mRNA, an RNA that contains the sequences of two or more genes.

polycistronic

Transcription regulation by an activator protein is considered to be _____________ control.

positive

Determine if it describes regulation at the transcription, translation or post-translation level. A protein is covalently modified.

posttranslation

Determine if it describes regulation at the transcription, translation or post-translation level. The product of a metabolic pathway inhibits the first enzyme in a pathway.

posttranslation

In an operon, the _________ signals the beginning of transcription.

promoter

The operon is flanked by a ______________ that signals the beginning of transcription and a _______________ that signals the end.

promoter; terminator

If gene regulation acts to prevent translation, what molecule will not be produced?

protein

The phenomenon in which the level of gene expression can vary under different conditions is gene ___________________.

regulation

The research of Monod and Jacob led to the initial understanding of gene ____________ stemmed from an interest in ____________ adaptation.

regulation; enzyme

Proteins that regulate the rate of transcription of target genes are called _______________ transcription factors.

regulatory

Jacob, Monod and Pardee formulated alternative hypotheses to explain the constitutive synthesis caused by the lacI- mutation. They proposed that the mutation either eliminated the function of the _______________ or that an internal _____________ was produced.

repressor; activator

The lac _____________ is inactivated by the binding to ____________.

repressor; allolactose

Repressors bind to ____________.

silencers

The binding of a small effector molecule to a regulatory protein changes the ________________ of the regulatory protein, which alters its DNA-binding ability.

structure

Would using a merozygote better indicate regulation of a gene by a trans-acting factor or a cis-acting element?

trans

When four molecules of allolactose are bound to the lac repressor, the lac operon is induced, and RNA polymerase ______________ the ____________.

transcribes; operon

The most common way that bacteria regulate gene expression is by influencing the rate of _____________ _____________.

transcription initiation

An enhancer is a DNA element that can be bound to a regulatory ______________ factor, which leads to ______ regulation.

transcription; up

Determine if it describes regulation at the transcription, translation or post-translation level. Antisense RNA binds to the mRNA.

translation

A glucocorticoid response element functions as a(n) ______.

enhancer

Transcription factor proteins contains regions called ____________ that have specific functions.

domains

Regulatory elements that inhibit transcription are called silencers and their effect on transcription is called ______ regulation.

down

Variation in ____________ _______________ orientation and location makes it difficult to study al the regions of DNA that affect the expression of a given gene.

regulatory elements

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

repressor

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

repressor

Determine if it describes regulation at the transcription, translation or post-translation level. Repressor proteins bind to an mRNA and prevent ribosome binding.

translation

You are studying a transcription factor that binds to DNA near a gene of interest. You discover that once the transcription factor binds, transcription of your gene of interest becomes undetectable. This is an example of __________ regulation.,

down

The binding of a small _____________ ______________ to a regulatory molecule alters the regulatory protein's conformation, and that alters the protein's ability to bind to _______.

effector molecule; DNA

LacIS mutations would result in a lac operon that is always ________________.

repressed

Determine if it describes regulation at the transcription, translation or post-translation level. A transcription terminator forms in the RNA.

transcription

Determine if it describes regulation at the transcription, translation or post-translation level. Genetic regulatory proteins bind to the DNA.

transcription

In bacteria, the most common way to regulate gene expression is by influencing the rate of __________________ initiation.

transcription

An inhibitor binds to an _________________ protein and prevents it from binding to DNA.

activator

Following the binding of a hormone, two glucocorticoid ____________ form a dimer and travel to the ______________.

receptor; nucleus

A ____________ ___________ is a protein that influences the ability of RNA polymerase to transcribe a given ______.

transcription factor; gene