Question 1

Which of the following statements best explains why transcription and translation can occur simultaneously in prokaryotes but not in eukaryotes?

Accepted Answer

Prokaryotes lack a nucleus, so ribosomes can access mRNA as it is being transcribed.

Question 2

During transcription, which enzyme synthesizes RNA from a DNA template, and what is a key difference between this enzyme and DNA polymerase?

Accepted Answer

RNA polymerase; it does not require a primer to initiate synthesis.

Question 3

A mutation changes the DNA sequence of a gene's promoter region. Which process is most likely to be directly affected?

Accepted Answer

Binding of RNA polymerase and initiation of transcription.

Question 4

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

Accepted Answer

It carries specific amino acids to the ribosome and matches its anticodon to the codon on mRNA.

Question 5

In eukaryotic cells, which of the following statements about RNA processing is correct?

Accepted Answer

Introns are removed from pre-mRNA by ribozymes before translation.

Question 6

A scientist observes a newly synthesized mRNA molecule in a eukaryotic cell. Which of the following must occur before this mRNA can be translated?

Accepted Answer

Removal of introns by ribozymes.

Question 7

Which of the following codons signals the start of translation, and what amino acid does it code for?

Accepted Answer

AUG; methionine

Question 8

A ribosome is translating an mRNA and encounters the codon UGA. What happens next?

Accepted Answer

Translation stops and the completed protein is released.

Question 9

Which of the following best describes the direction in which RNA is synthesized during transcription?

Accepted Answer

5' → 3'

Question 10

A mutation in a eukaryotic gene results in the failure to remove introns from the pre-mRNA. What is the most likely consequence?

Accepted Answer

The resulting protein will be abnormal due to the presence of noncoding sequences.

Question 11

Which of the following correctly matches the ribosomal site with its function during translation?

Accepted Answer

A site: entry of incoming tRNA; P site: holds the growing peptide chain.

Question 12

Which of the following is NOT a function of rRNA?

Accepted Answer

Carrying amino acids to the ribosome.

Question 13

A researcher is studying a prokaryotic cell and observes that translation begins before transcription is complete. Which structural feature of prokaryotes allows this to happen?

Accepted Answer

Absence of a nuclear membrane.

Question 14

Which of the following sequences is a stop codon in mRNA?

Accepted Answer

UAG

Question 15

During translation, what is the role of the anticodon on tRNA?

Accepted Answer

It base-pairs with the complementary codon on mRNA to ensure the correct amino acid is added.

Question 16

Which of the following best describes the relationship between exons and introns in eukaryotic genes?

Accepted Answer

Exons are coding regions that remain in mature mRNA, while introns are noncoding regions that are removed.

Question 17

A patient has a genetic disorder caused by a mutation that prevents ribozymes from functioning. Which process is most directly affected?

Accepted Answer

Removal of introns from pre-mRNA in eukaryotes.

Question 18

Which of the following best explains why mRNA must be processed in eukaryotes before translation can occur?

Accepted Answer

To remove noncoding introns and produce a mature mRNA that can be translated.

Question 19

A mutation causes a tRNA molecule to have an incorrect anticodon sequence. What is the most likely result during translation?

Accepted Answer

The tRNA may pair with the wrong codon, leading to incorporation of an incorrect amino acid.

Question 20

Which of the following steps occurs first during the process of translation?

Accepted Answer

Assembly of the small and large ribosomal subunits into an active ribosome.

chapter 8 part 4

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