Question 1

Which of the following best describes the process of transcription in eukaryotic cells?

Accepted Answer

The synthesis of an RNA strand from a DNA template, catalyzed by RNA polymerase.

Question 2

Given the following DNA template strand sequence (3'–TAC GGA TCC GTT–5'), what is the corresponding mRNA sequence produced during transcription?

Accepted Answer

$$5'–AUG CCU AGG CAA–3'$$

Question 3

Which of the following statements correctly compares gene expression in bacteria and eukaryotes?

Accepted Answer

In bacteria, transcription and translation can occur simultaneously in the cytoplasm.

Question 4

A mutation changes the codon $$5'–GAA–3' ($$which codes for glutamic acid) to $$5'–GAG–3'. $$What type of mutation is this, and what is its likely effect on the protein?

Accepted Answer

Silent mutation; no change in the amino acid sequence.

Question 5

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

Accepted Answer

A site

Question 6

If the non-template (coding) DNA strand is $$5'–ATG TTT GGC–3'$$, what is the first three amino acids in the polypeptide produced?

Accepted Answer

Methionine–Phenylalanine–Glycine

Question 7

Which of the following best explains why alternative splicing increases protein diversity in eukaryotes?

Accepted Answer

It enables a single gene to produce multiple mRNA variants, leading to different protein products.

Question 8

A mutation introduces a premature stop codon in the middle of a gene. What is the most likely consequence for the resulting protein?

Accepted Answer

The protein will be truncated and likely nonfunctional.

Question 9

Which of the following modifications occurs to eukaryotic pre-mRNA before it is exported from the nucleus?

Accepted Answer

Addition of a 5' cap and a 3' poly-A tail

Question 10

Given the mRNA sequence $$5'–AUG UUU UGA CCG–3'$$, use the codon table to determine the resulting polypeptide sequence.

Accepted Answer

Methionine–Phenylalanine

Question 11

Which of the following best describes the direction in which RNA polymerase synthesizes mRNA during transcription?

Accepted Answer

It reads the template DNA strand in the $$3' \rightarrow 5'$$ direction and synthesizes mRNA in the $$5' \rightarrow 3'$$ direction.

Question 12

A tRNA has the anticodon $$3'–UAC–5'. $$Which mRNA codon will it recognize, and which amino acid will it carry?

Accepted Answer

Codon $$5'–AUG–3'$$; Methionine

Question 13

If RNA splicing fails to occur in a eukaryotic cell, what is the most likely consequence?

Accepted Answer

The mature mRNA will contain introns, potentially leading to nonfunctional proteins.

Question 14

Which of the following is NOT a function of the ribosome during translation?

Accepted Answer

Synthesizing mRNA from a DNA template.

Question 15

A frameshift mutation occurs due to the insertion of a single nucleotide in the coding region of a gene. What is the most likely effect on the resulting protein?

Accepted Answer

The reading frame is altered, potentially changing every amino acid downstream of the mutation.

Question 16

Which of the following best explains why many mutations have no effect on phenotype?

Accepted Answer

Some mutations occur in non-coding regions or are silent mutations that do not change the amino acid sequence.

Question 17

Which of the following events occurs during transcription initiation in eukaryotes?

Accepted Answer

RNA polymerase binds to the promoter region of the gene.

Question 18

Why might the initial polypeptide produced during translation not be functional?

Accepted Answer

It must undergo folding and post-translational modifications to become active.

Question 19

Which of the following best describes the flow of genetic information in the central dogma of molecular biology?

Accepted Answer

DNA $$\rightarrow$$ RNA $$\rightarrow$$ Protein

Gene Expression: From Gene to Protein (Transcription and Translation)

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