Chapter 13 bio

A strain of bacteria containing F factor genes is called a

. merozygote.

The major difference in gene regulation between prokaryotes and eukaryotes is

Eukaryotic genes are arranged individually, while prokaryotic genes are grouped into operons.

A mutation in the CAP protein occurs such that it permanently binds cAMP. What is the likely effect on lac operon gene expression when glucose concentration decreases and lactose is present?

Lac operon gene expression will permanently increase until lactose is used up.

What would be the most likely outcome for a cell if a gene expressed at relatively constant but low levels were mutated to dynamically respond to environmental changes?

The cell would likely have more and less protein at different times that would affect cellular function.

The lacA gene found within the lac operon encodes for galactosidase transacetylase. This enzyme attaches a(n) ________ group to lactose and lactose analogs.

acetyl

The likely outcome from a mutation in the lacO site (lac Operator) of the lac operon would be

binding of a repressor protein could be hindered.

The ability of glucose to repress the lac operon depends on which effector molecules?

cAMP

Liver cells, mammary cells, and skin cells all contain the same genome; however, their respective proteomes vary drastically. This observation is best explained by what phenomenon?

cell differentiation

The lac operator site within the lac operon is an example of a

cis-acting element.

A eukaryotic gene that is regulated by three activator proteins is said to be under

combinatorial control.

Genes expressed at relatively constant levels in tissues regardless of variations in the animal's condition are called a

constitutive gene.

Genes organized into an operon are beneficial to certain bacteria because the operon allows for

coordinated regulation of a group of genes that encode proteins with a common function.

Eukaryotic DNA methylation occurs on which base?

cytosine

The mediator protein complex in eukaryotes

facilitates interactions between RNA polymerase II and regulatory transcription factors.

Once the lac repressor binds to the lac operator site, RNA polymerase is prevented from transcribing the

galactosidase and galactoside transacetylase genes.

A cell's ability to control their level of gene expression is called

gene regulation.

When cytosolic levels of iron increase, intracellular ferritin levels will

increase.

DNA methylation

inhibits transcription.

What would be the most likely outcome if the promoter for operon structural genes became mutated so that only constitutive expression was possible?

polycistronic mRNA would still be produced

An mRNA that contains the coding sequence for two or more structural genes is called a

polycistronic mRNA.

The general transcription factor TFIID

recognizes the TATA box.

Small effector molecules

regulate gene transcription by binding a regulatory protein.

A(n) ________ operon is one whose transcription is decreased by effector molecules.

repressible

An activator is to an enhancer as a(n) _____ is to a silencer.

repressor

MicroRNAs (miRNAs)

silence the expression of specific mRNAs.

The lacP site within the lac operon is upstream of the genes that encode for lactose uptake and metabolism proteins. The lacP site is

the lac promoter site where RNA polymerase binds.

The event that occurs in E. coli when lactose is absent from its environment is

trace amounts of b-galactosidase, lactose permease, and galactoside transacetylase are made.

The event that occurs when allolactose levels increase in E. coli is

transcription of genes within the lac operon increases.

The core promoter in eukaryotes is usually composed of which two features?

transcriptional start site and TATA box

The molecule that functions as a corepressor for the trp operon is

tryptophan.

A polycistronic mRNA is produced from genes A, B, and F. If the translation initiation site was mutated between genes B and F, what would be the likely outcome?

A single polyintronic mRNA that produces 2 proteins A-B and B.

A gene that has 3 exons A, B and C and 2 introns undergoes alternative splicing. If B and C have a low frequency splice site, what is the most likely mRNA pool that would result from gene expression?

A-C, A-B, and C

What could be a possible consequence if a structural gene's TATA box is mutated?

All of the choices are correct.

Histone deacetylase inhibitors are a class of drugs used as mood stabilizers and anti-epileptics that are also being researched for their efficacy as anti-cancer agents. Histone deacetylase inhibitors block the action of histone deacetylases, which remove acetyl groups from lysine residues in histone tails. How will blocking histone deacetylases affect gene expression in the cell?

Chromatin will become more open, and gene expression will be increased

A bacteria contains two copies of the lac operon; one on the bacterial chromosome and one on a plasmid. The lacO site on the chromosomal lac operon is mutated and non-functional whereas the lacO site on the plasmid is functional. What is the most likely outcome for the bacterial cell when glucose is declining and lactose is present?

Expression of lac structural genes on the chromosome and plasmid will increase because repressor proteins are unable to bind one but not the other lacO site.

Certain drugs use RNA interference as a mechanism of action. What molecule would the active compounds of these drugs be composed of?

Nucleic acid

Why would bacteria evolve so that the presence of tryptophan inhibits its own production?

Producing the enzymes that synthesize tryptophan is metabolically expensive, so it is wasteful to make them when tryptophan levels are high and its synthesis is not necessary.

What happens when the cAMP-CAP complex binds the CAP site near the lac promoter?

RNA polymerase binds to the promoter and transcription rate increases.

Events that occur during transcriptional regulation in eukaryotes include

RNA processing and export from the nucleus.

Jacob, Monod, and Pardee constructed a mutant strain of E. coli that carried a lacI-gene mutation (encodes the lac repressor). Which is TRUE of this mutant strain?

The lac operon is constitutively expressed.

Which of the following is NOT true of the glucocorticoid receptor?

When bound to glucocorticoids, the receptors will bind covalently and irreversibly to each other to form dimers.

What type of regulatory transcription factor binds DNA and increases the transcription of a gene?

an activator exerting positive control

A motif structure NOT commonly found in transcription factor proteins is

arginine helix-loop-zipper motif