Question 1

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 2

During transcription in eukaryotic cells, which enzyme is primarily responsible for synthesizing mRNA from a DNA template?

Accepted Answer

RNA polymerase II

Question 3

A mutation changes a codon from UAU to UAA. What is the most likely effect on the resulting protein?

Accepted Answer

The protein will be prematurely terminated.

Question 4

Which of the following statements about the structure of DNA and RNA is correct?

Accepted Answer

DNA is usually double-stranded, while RNA is usually single-stranded.

Question 5

If a segment of DNA has the sequence 5'-ATGCGT-3', what is the sequence of the complementary mRNA strand produced during transcription?

Accepted Answer

5'-UACGCA-3'

Question 6

Which of the following best describes the function of tRNA during translation?

Accepted Answer

It carries amino acids to the ribosome and matches them to the coded mRNA message.

Question 7

A researcher observes that a certain gene is not expressed in a cell. Which of the following could explain this observation?

Accepted Answer

The gene's promoter region is methylated, preventing RNA polymerase binding.

Question 8

Which process involves the removal of introns from a pre-mRNA transcript?

Accepted Answer

Splicing

Question 9

Which of the following is a possible consequence of a frameshift mutation in a gene?

Accepted Answer

The resulting protein is likely to be nonfunctional due to extensive missense.

Question 10

Which of the following best explains why the genetic code is described as 'redundant but not ambiguous'?

Accepted Answer

Multiple codons can code for the same amino acid, but each codon specifies only one amino acid.

Question 11

During translation, which site on the ribosome does the incoming aminoacyl-tRNA first bind?

Accepted Answer

A site

Question 12

Which of the following is NOT a step in the process of translation?

Accepted Answer

Replication

Question 13

A patient is diagnosed with sickle cell anemia, which is caused by a single nucleotide substitution in the hemoglobin gene. What type of mutation is this?

Accepted Answer

Missense mutation

Question 14

Which of the following sequences is most likely to be a promoter region in a eukaryotic gene?

Accepted Answer

TATAAA

Question 15

Which of the following best describes the role of the poly-A tail added to eukaryotic mRNA?

Accepted Answer

It protects mRNA from degradation and assists in export from the nucleus.

Question 16

If a gene is transcribed but not translated, what is the most likely product?

Accepted Answer

An RNA molecule

Question 17

Which of the following is a function of rRNA in the ribosome?

Accepted Answer

It catalyzes peptide bond formation between amino acids.

Question 18

A scientist introduces a mutation that removes the stop codon from an mRNA. What is the most likely result?

Accepted Answer

The ribosome will continue translating into the poly-A tail, producing a nonfunctional protein.

Question 19

Which of the following best explains why a single base insertion in a coding region can have a dramatic effect on protein function?

Accepted Answer

It causes a frameshift, altering the reading frame of the gene.

Question 20

Which of the following is true regarding the difference between prokaryotic and eukaryotic gene expression?

Accepted Answer

In eukaryotes, mRNA is processed before translation, including splicing and addition of a 5' cap and poly-A tail.

Gene Expression: From Gene to Protein (Ch. 17) Study Guide

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