Chapter 12

25問 • 1年前

問題一覧

Genes that encode proteins are first transcribed to mRNA, and then are translated into protein. What is the MOST important factor in determining the control of gene expression?

The level of transcription (when a gene is transcribed into mRNA)

A major difference in gene regulation between prokaryotes and eukaryotes is that….

eukaryotic genes are arranged individually, while prokaryotic genes are grouped into opérons

A cells ability to control their level of gene expression is called?

gene regulation

A scientist uses recombinant technology to take a eukaryotic promoter and place it in front of a bacterial structural gene. What is the most likely outcome in bacterial gene expression?

Bacterial gene expression will not occur because RNA polymerase enzymes between prokaryotes and eukaryotes are incompatible.

Which of the following is NOT true of small effector molecules?

They can regulate gene transcription by binding to DNA

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

coordinated regulation of a group of genes that encode proteins in a common pathway

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

cAMP

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

acetyl

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 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 the lacO site does not affect the CAP protein that activates the operon.

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

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

polycistronic mRNA

A mutation in the gene that encodes the CAP protein occurs such that the CAP protein permanently binds cAMP. How is regulation of the lac operon likely to be different in a bacterium with the mutation compared to a normal bacterium?

When there is high lactose and high glucose in the environment, the lac operon genes will be expressed at high levels in the mutant and low levels in normal bacteria.

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

binding of a repressor protein could be hindered

Small effector molecules

regulate gene transcription by binding a regulatory protein.

When the lac repressive binds to the lac operator site, RNA polymerase is prevented from transcribing which gene(s)?

The galactosidase and galactoside transacetylase genes

What happens when allolactose levels increase in E.Coli?

Transcription of genes within the lac operon increases.

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

all of these choices are correct

What type of regulatory transcription factor binds DNA in order to increase the transcription of a gene?

An activator exerting positive control

The general transcription factor TFIID

recognizes the TATA box.

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

transcriptional start site and TATA box

DNA methylation

inhibits transcription

Eukaryotic DNA methylation occurs on which base?

cytosine

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.

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

cell differentiation

When cytosolic levels of iron increase, intracellular ferritin levels will

increase

chapter 21

Madeline Joslyn · 46回閲覧 · 25問 · 1年前

chapter 21