Question 1

Which of the following best describes the role of the sigma protein in bacterial transcription initiation?

Accepted Answer

It recognizes promoter sequences and orients RNA polymerase on the DNA.

Question 2

During eukaryotic mRNA processing, which sequence of events occurs before the mRNA is exported to the cytoplasm for translation?

Accepted Answer

Addition of a 5' cap, removal of introns, and addition of a poly(A) tail

Question 3

A mutation in the promoter region of a bacterial gene alters the -10 box sequence. What is the most likely effect on transcription?

Accepted Answer

Transcription will likely decrease or fail to initiate due to poor sigma recognition.

Question 4

Which of the following statements about the template and coding strands of DNA is correct?

Accepted Answer

The template strand is complementary to the mRNA sequence.

Question 5

In eukaryotes, which of the following is a direct consequence of alternative RNA splicing?

Accepted Answer

A single gene can produce multiple protein isoforms.

Question 6

Which enzyme is responsible for 'charging' tRNAs with their corresponding amino acids?

Accepted Answer

Aminoacyl-tRNA synthetase

Question 7

A scientist observes that a single tRNA can recognize multiple codons for the same amino acid. Which concept explains this phenomenon?

Accepted Answer

Wobble pairing at the third position of the codon

Question 8

Which of the following best explains why transcription and translation are coupled in bacteria but not in eukaryotes?

Accepted Answer

Bacterial mRNA does not require processing and both processes occur in the cytoplasm.

Question 9

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

Accepted Answer

A site

Question 10

A mutation prevents the addition of the 5' cap to a eukaryotic mRNA. What is the most likely consequence?

Accepted Answer

The mRNA will be rapidly degraded and poorly translated.

Question 11

Which of the following events occurs during the elongation phase of translation?

Accepted Answer

A peptide bond forms between the amino acid in the A site and the polypeptide in the P site.

Question 12

Which of the following is true regarding the termination of transcription in bacteria?

Accepted Answer

An RNA hairpin forms, causing RNA polymerase to dissociate from the DNA.

Question 13

If a eukaryotic cell is treated with a drug that inhibits spliceosome function, what is the most likely outcome?

Accepted Answer

Primary transcripts will retain introns and may not be properly translated.

Question 14

Which of the following best describes the function of the large ribosomal subunit during translation?

Accepted Answer

It is the site where peptide bonds are formed between amino acids.

Question 15

A mutation changes a codon in the middle of an mRNA from UAU (tyrosine) to UAA. What is the most likely effect on translation?

Accepted Answer

Translation will terminate prematurely at the mutated codon.

Question 16

Which of the following is a key difference between bacterial and eukaryotic transcription termination?

Accepted Answer

Bacteria use an RNA hairpin structure, while eukaryotes use a poly(A) signal.

Question 17

Which of the following best explains why there are fewer tRNAs than codons?

Accepted Answer

Some tRNAs can recognize multiple codons due to wobble pairing.

Question 18

Which of the following is NOT a function of the 3' poly(A) tail in eukaryotic mRNA?

Accepted Answer

Enabling ribosome binding during translation initiation

Question 19

A researcher isolates a mature eukaryotic mRNA and finds that it contains regions at both ends that are not translated into protein. What are these regions called?

Accepted Answer

Untranslated regions (UTRs)

Question 20

Which of the following best describes the direction in which a polypeptide chain grows during translation?

Accepted Answer

Amino acids are added to the carboxyl (C) terminus.

Chapter 17: Transcription and Translation – From DNA to Protein

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