Question 1

Which property of the genetic code allows multiple codons to specify the same amino acid?

Accepted Answer

It is degenerate

Question 2

According to the wobble hypothesis, which codon position is most likely to vary without changing the amino acid specified?

Accepted Answer

Third position

Question 3

A mutation in the operator (O) region of the lac operon in E. coli would most likely result in:

Accepted Answer

Constitutive expression of the lac operon

Question 4

Which of the following best explains why the human phenylalanine hydroxylase gene is 90,000 bases long, but its mature mRNA is only 2,400 bases?

Accepted Answer

Presence of introns in DNA

Question 5

During bacterial translation initiation, how is the mRNA oriented on the ribosome?

Accepted Answer

By the Shine–Delgarno sequence base-pairing with rRNA

Question 6

Which of the following is a function of the poly(A) tail in eukaryotic mRNA?

Accepted Answer

All of the above

Question 7

A tRNA synthetase mutation causes glycine to be attached to tRNA^Val instead of valine. What will be the result during translation?

Accepted Answer

Glycines at all glycine positions and at all valine positions

Question 8

Which site on the ribosome do charged tRNAs enter during the elongation phase of translation?

Accepted Answer

A site

Question 9

Which of the following is a good example of polycistronic RNA?

Accepted Answer

The presence of lacZ, lacY, and lacA genes on the same mRNA

Question 10

Which of the following is a trans-acting element?

Accepted Answer

TrpR protein, LacI protein, and CAP

Question 11

What is the effect of histone acetylation on gene expression?

Accepted Answer

It causes an increase in expression

Question 12

Which of the following best describes the role of DNA methylation in eukaryotes?

Accepted Answer

To aid in silencing transcription

Question 13

Which sequence in eukaryotic transcription is homologous to the Pribnow box in prokaryotes?

Accepted Answer

Goldberg–Hogness box (TATA box)

Question 14

Which of the following statements about enhancers is correct?

Accepted Answer

They can be inverted without altering function

Question 15

Which of the following best describes the ENCODE project's finding that 80% of the human genome is biochemically functional?

Accepted Answer

80% of the genome is bound by proteins, transcribed, or bound by histones

Question 16

Which of the following is true about the regulation of gene expression in eukaryotes?

Accepted Answer

It occurs at multiple levels including transcription, splicing, mRNA degradation, and translation

Question 17

What is the role of general transcription factors (GTFs) in eukaryotic transcription?

Accepted Answer

They bind to the core promoter and allow transcriptional initiation

Question 18

Which of the following best describes the difference between the Initiator element (Inr) and the TATA box in eukaryotic transcription?

Accepted Answer

RNA polymerase binds to the TATA box and initiates transcription downstream at the Inr

Question 19

Which of the following is most analogous to an enhancer in prokaryotes?

Accepted Answer

Operator

Question 20

A mutation in an aminoacyl tRNA synthetase causes it to attach the wrong amino acid to a tRNA. Which property of the genetic code allows the ribosome to still translate the mRNA, but with errors?

Accepted Answer

The ribosome does not check the amino acid, only the anticodon

Genetics: Key Concepts in the Genetic Code, Transcription, Translation, and Gene Regulation

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