Deck 18: Post-Transcriptional Regulation in Eukaryotes

Question 1

Having two copies of the X- chromosome gene_______initiates the female sex- determining pathway by which gene regulatory mechanism?

A)DSX; alternative polyadenylation
B)DSX; alternative splicing
C)TRA; alternative splicing
D)SXL; alternative splicing
E)SXL; alternative polyadenylation

Answer 1

SXL; alternative splicing

Question 2

What is the general name of enzymes that add phosphate groups to protein targets?

A)proteases
B)acetylases
C)kinases
D)phosphatases
E)ligases

Answer 2

C

Question 3

A researcher is studying plant development.She isolates a mutant and discovers that the piece of DNA that is mutated does not code for a protein.However,this piece of DNA is complimentary to a gene known to function in early embryonic plant development.The mutant she identified most likely functions as an_______.

A)general transcription factor known to regulate many different genes
B)ribosomal RNA rRNA)
C)microRNA miRNA)
D)transfer RNA tRNA)
E)intron

Answer 3

C

Question 4

In regards to mRNA stability,what is the effect of decapping enzymes?

A)The m⁷G cap of mRNAs is removed causing mRNAs to be degraded from the 5' end.
B)The splicing of mRNAs is blocked,which destabilizes mRNAs.
C)The m⁷G cap of mRNAs is stabilized allowing mRNAs to be protected at the 5' end.
D)The polyadenylation of mRNAs is stabilized allowing mRNAs to be protected at the 3' end.
E)The polyadenylation of mRNAs is removed and mRNAs are degraded from the 3' end.

Question 5

microRNA miRNA and small interfering RNA siRNA)use a similar process and proteins to regulate gene expression.Which of the following is more commonly associated with the miRNA pathway?

A)The protein AGO is found in the miRNA pathway but not the siRNA pathway.
B)The protein complex RISC is found in the miRNA pathway but not the siRNA pathway.
C)The protein Drosha is found in the miRNA pathway but not the siRNA pathway.
D)In animals,the miRNA pathway usually leads to mRNA degradation,and in the siRNA pathway,the mRNA is not degraded.
E)The protein Dicer is found in the miRNA pathway but not the siRNA pathway.

Question 6

Which of the following is the most common type of alternative splicing in animals and involves making mRNA molecules that lack a complete exon?

A)intron retention
B)mutually exclusive exons
C)cassette exons
D)alternative promoters
E)alternative splice site

Question 7

Which of the following statements is most true regarding long noncoding RNAs lncRNAs ?

A)lncRNAs do not contain a 5' guanine cap or a 3' poly- A- tail.
B)Some lncRNAs will decrease the activity of miRNAs.
C)Some lncRNAs regulate alternative splicing.
D)lncRNAs are characteristically about the same size as sncRNAs.
E)lncRNAs act only as posttranscriptional regulators and never as pretranscription regulators.

Question 8

What posttranslational modification occurs on the protein CPEB to initiate mRNA translation?

A)phosphorylation
B)acetylation
C)ubiquitination
D)methylation
E)glycosylation

Question 9

Adenosine-uridine- rich elements are_______.

A)trans- acting elements that bind to mRNA to either degrade or stabilize mRNA
B)trans- acting elements that bind to mRNA to recruit ribosomes to mRNA for translation initiation
C)cis- acting elements where ribosomes bind to in order to initiate translation
D)cis- acting elements that recruit RNA- binding proteins to mRNA to either degrade or stabilize the mRNAs
E)trans- acting elements that block mRNA splicing

Question 10

Which of the following statements is predicted if a population of fruit flies were fed a chemical that blocked the function of the SXL protein?

A)The mRNA produced from the doublesex dsx)gene would not be spliced.
B)The progeny in the next generation would be predominantly male.
C)The progeny in the next generation would be approximately 50% male and 50% female.
D)The progeny in the next generation would be predominantly female.
E)The transformer tra)gene would be maximally expressed.

Question 11

mRNA surveillance mechanisms are necessary_______ .

A)to recruit general transcription factors to the promoter
B)in determining which alternative splice site should be used
C)to eliminate mRNAs with a premature stop codon
D)for polyadenylation at the 3' end of mRNA
E)to measure the concentration of mRNAs in the cytoplasm

Question 12

The discovery of RNA interference RNAi)led to its use in biotechnology and medicine.All of the following are examples of how RNAi could be used in biotechnology or medicine,EXCEPT _______.

A)to treat a disease characterized by the overexpression of a nonmutated gene
B)to study loss- of- function phenotypes of specific genes in a model research organism
C)to treat a disease characterized by the buildup of a specific protein
D)to treat a disease characterized by the normal expression of a mutated gene
E)to treat a disease characterized by a gene that is not expressed

Question 13

If the protein Dicer is not functioning,then which kind of posttranscriptional gene regulation is most likely affected?

A)only microRNA miRNA),but not small interfering RNA siRNA
B)alternative adenylation
C)alternative splicing
D)microRNA miRNA)and small interfering RNA siRNA
E)small interfering RNA siRNA

Question 14

_______iare cytoplasmic structures that will aggregate mRNA molecules for either degradation or later translation.

A)Processing bodies
B)Ribosomes
C)Golgi apparatus
D)Proteasomes
E)Mitochondria

Question 15

Which protein modification is most closely linked to protein degradation?

A)ubiquitination
B)phosphorylation
C)glycosylation
D)methylation
E)acetylation

Question 16

Mutations that affect SR proteins will have what kind of effect on gene expression?

A)Splicing of the mRNA will not be activated.
B)General transcription factors will be unable to bind to promoters.
C)RNA polymerase will be unable to terminate transcription.
D)Ribosomes will not be able to bind to mRNA molecules in the cytoplasm.
E)Polyadenylation at the 3' end will be blocked.

Question 17

The human disease spinomuscular atrophy is caused by a failure of which posttranscription regulatory mechanism?

A)alternative polyadenylation
B)RNA interference
C)mRNA surveillance
D)translation initiation
E)alternative splicing

Question 18

In a eukaryote,what is the best way to compare the number of genes in a genome to the number of proteins that the genome can produce and why?

A)The number of proteins is equivalent to the number of genes due to alternative splicing.
B)The number of proteins is usually fewer than the number of genes due to alternate splicing.
C)The number of proteins is usually greater than the number of genes due to alternate splicing.
D)The number of proteins is usually greater than the number of genes due to histone modification.
E)The number of proteins is usually fewer than the number of genes due to histone modification.

Question 19

A long poly- A- tail is necessary to initiate translation.Which protein binds directly to eIF4E to inhibit translation initiation?

A)maskin
B)PABP
C)CPEB
D)PARN
E)poly- A polymerase

Question 20

A particular fibroblast mutation fails to move to the site of infection.It is discovered that this mutation causes a particular protein to be absent,which leads to premature actin mRNA translation.Which protein is most likely absent due to the mutation?

A)poly- A polymerase
B)CPEB
C)ZBP1 zip code- binding protein
D)general transcription factor
E)Src

Question 21

A particular mutant was found that produced a protein that was longer lived than its normal protein.Upon sequencing the mutant,the researcher discovered that specific lysine amino acids had been changed to arginines.Propose a model of what this mutation caused to allow the proteins to be longer lived.

Question 22

What are two features of circular RNAs cirRNAs)that limit their ability to be degraded?

Question 23

What is nonsense- mediated decay,why is it important,and what is a proposed mechanism as to how it works?

Question 24

List three general pathways in which eukaryotic mRNA is typically degraded in eukaryotes.

Question 25

Cancer is caused by many different types of gene mutations.Some mutations are in proto- oncogenes,which lead to overexpression of the genes,and other mutations are in tumor suppressor genes,which lead to under expression or no expression in these genes.Which kinds of gene mutations would RNA interference RNAi)be better at treating? Explain.

Question 26

Mutating the gene Transformer tra)in Drosophila that is chromosomally XX leads to the development of only males.Explain.

Question 27

Describe how cells control the size of the poly- A tail on mRNA molecules in order to regulate translation initiation. Next explain how a kinase inhibitor could decrease gene expression in regards to polyadenylation? Your answer should include the following proteins in your answer: Maskin, PARN, CPEB, eIF4E, eIF4G, and Poly- A polymerase.

Question 28

Compare and contrast kinases and phosphatases.

Question 29

What is the general gene regulation mechanism that "cassette exons" and "intron retention" are involved with? Explain their differences in regards to which kinds of organism use each and how each is different in what they do.