Question 1

Considering the E.coli trp operon, which of the following is TRUE? I.The formation of the 2-3 hairpin is highly favored over the 1-2 hairpin when trp is low. II.When the concentration of Trp-tRNA^Trp is low, the ribosome halts on tandem Trp codon of segment 1. III.Formation of the 2-3 hairpin facilitates transcription and translation of the trp operon. IV.The attenuator system has no effect when Trp levels are high.

Accepted Answer

I is false because the formation of the 1-2 hairpin (not the 2-3 hairpin) is highly favored when trp levels are low. 
III is false because formation of the 2-3 hairpin actually inhibits transcription and translation by causing termination of RNA polymerase. 
IV is false because the attenuator system is active when trp levels are high, and it serves to regulate the expression of the operon. Therefore, only II and III are true statements, and the correct choice is C.

Question 2

On average a single nucleotide polymorphism occurs ____ in humans.

Accepted Answer

The answer of On average a single nucleotide polymorphism occurs...

Question 3

In prokaryotes, which of the following are effective at controlling gene expression relative to the concentration of a metabolite or catabolite?
I.CAP or CRP
II.long terminal repeats (LTRs)
III.riboswitches
IV.SWI/SNF

Accepted Answer

CAP or CRP, long terminal repeats (LTRs), and riboswitches are all effective at controlling gene expression relative to the concentration of a metabolite or catabolite in prokaryotes. SWI/SNF is not involved in this type of regulation. Therefore, the correct answer is choice C, which includes only CAP or CRP and riboswitches.

Question 4

Which of the following would likely result in the formation of RNAi?

Accepted Answer

The answer of Which of the following would likely result...

Question 5

Which of the following genes rarely occur in multiple copies?
I.histone proteins
II.protein-coding genes
III.gene clusters

Accepted Answer

Histone proteins rarely occur in multiple copies, but both protein-coding genes and gene clusters can exist in multiple copies. Therefore, only option D, "II only", fits the criteria of a gene that rarely occurs in multiple copies.

Question 6

Of the human genome approximately 80% ___.

Accepted Answer

Approximately 80% of the human genome may be transcribed, meaning it has the potential to be turned into RNA. This includes both exonic DNA, which codes for proteins, as well as non-coding DNA that can still be transcribed into RNA for various regulatory functions. Only a small portion of the genome, around 2%, is made up of protein-encoding genes (choice C).

Question 7

Which of the following is TRUE regarding eukaryotic mRNAs?
I.They uniformly stable.
II.The poly (A)tail appears to partially Moderate the rate of degradation.
III.The 5' cap appears to partially Moderate the rate of degradation.
IV.They have decay times ranging from 10-30 minutes.

Accepted Answer

Eukaryotic mRNAs are not uniformly stable, making statement I false. However, statements II and III are true. The poly (A)tail and the 5' cap both play a role in moderating the rate of degradation. Statement IV is not entirely true, as the decay times for eukaryotic mRNAs can vary widely depending on factors such as the sequence and secondary structure of the mRNA. The range given in statement IV is therefore inaccurate. Therefore, the best choice is B, as it includes the two true statements about eukaryotic mRNAs.

Question 8

The process of somatic recombination
I.results in antibody diversity.
II.involves selection of individual members of clustered gene sequences.
III.involves selection and recombination of specific exons on the F1F1F1S1F1F1F10 and/or F1F1F1S1F1F1F10 chain.

Accepted Answer

Somatic recombination is the process that generates the diversity of antibodies. It involves the selection and recombination of specific exons on the F1F1F1S1F1F1F10 and/or F1F1F1S1F1F1F10 chain, and it also involves the selection of individual members of clustered gene sequences. Therefore, all three statements are correct.

Question 9

Which of the following are requirements for genetic information?
I.Information must be tapped in an orderly fashion.
II.Information must be available to direct responses in changes to internal or external conditions.
III.Information must be removable following development.

Accepted Answer

I - Orderly fashion is necessary for storing genetic information so that it can be accessed and understood properly.

II - Genetic information is needed to direct responses to internal or external changes, such as growth, development, and response to stimuli.

III - Genetic information should not be removable following development and it should be passed down from generation to generation. Therefore, this statement is incorrect.

Both I and II are necessary requirements for genetic information, whereas III is not. Therefore, the best choice is B.

Question 10

Progression through the cell cycle
I.is regulated by cyclins.
II.is controlled by Cdks.
III.is altered by CKIs.

Accepted Answer

The progression through the cell cycle is regulated by cyclins, controlled by Cdks, and altered by CKIs. Therefore, all three options are correct and the answer is E - I, II, III.

Quiz 28: Regulation of Gene Expression

On average a single nucleotide polymorphism occurs ____ in humans.

In prokaryotes, which of the following are effective at controlling gene expression relative to the concentration of a metabolite or catabolite? I.CAP or CRP II.long terminal repeats (LTRs) III.riboswitches IV.SWI/SNF

Which of the following would likely result in the formation of RNAi?

Which of the following genes rarely occur in multiple copies? I.histone proteins II.protein-coding genes III.gene clusters

Of the human genome approximately 80% ___.

Which of the following is TRUE regarding eukaryotic mRNAs? I.They uniformly stable. II.The poly (A) tail appears to partially Moderate the rate of degradation. III.The 5' cap appears to partially Moderate the rate of degradation. IV.They have decay times ranging from 10-30 minutes.

The process of somatic recombination I.results in antibody diversity. II.involves selection of individual members of clustered gene sequences. III.involves selection and recombination of specific exons on the  and/or  chain.

Which of the following are requirements for genetic information? I.Information must be tapped in an orderly fashion. II.Information must be available to direct responses in changes to internal or external conditions. III.Information must be removable following development.

Progression through the cell cycle I.is regulated by cyclins. II.is controlled by Cdks. III.is altered by CKIs.