Question 1

Which of the following best describes the role of the poly(A) tail in eukaryotic mRNA?

Accepted Answer

It increases mRNA stability and prolongs its lifespan in the cytoplasm.

Question 2

A mutation changes the codon UUU to UUC in an mRNA. What is the likely effect on the resulting protein?

Accepted Answer

The amino acid sequence will remain unchanged due to redundancy in the genetic code.

Question 3

During translation initiation in eukaryotes, which event occurs first?

Accepted Answer

The small ribosomal subunit binds to the 5' cap of the mRNA and scans for the start codon.

Question 4

What is the function of aminoacyl-tRNA synthetase in translation?

Accepted Answer

It attaches the correct amino acid to its corresponding tRNA using ATP.

Question 5

Given the mRNA sequence 5' AUGGCCUAA 3', what is the resulting amino acid sequence?

Accepted Answer

Met-Ala-Stop

Question 6

Which of the following statements about tRNA is correct?

Accepted Answer

The anticodon is complementary and antiparallel to the mRNA codon.

Question 7

What is the role of ribosomal RNA (rRNA) in the ribosome during translation?

Accepted Answer

It acts as a ribozyme, catalyzing peptide bond formation in the large subunit.

Question 8

Which process is directly regulated by microRNAs (miRNAs) in eukaryotic cells?

Accepted Answer

Translation by binding to complementary mRNA sequences and preventing ribosome access

Question 9

A scientist observes that a protein is not functional until a segment is removed from its N-terminus. Which type of regulation is this?

Accepted Answer

Post-translational regulation

Question 10

Which of the following best explains why multiple ribosomes can translate a single mRNA simultaneously?

Accepted Answer

Ribosomes move along the mRNA, allowing new ribosomes to initiate translation before the previous one finishes, forming a polyribosome.

Question 11

Which of the following is a direct effect of increasing the length of the poly(A) tail on an mRNA molecule?

Accepted Answer

Increased stability and longer lifespan of the mRNA

Question 12

What is the correct order of the steps in translation?

Accepted Answer

Initiation, Elongation, Termination

Question 13

Which of the following mechanisms can regulate the accessibility of mRNA to ribosomes?

Accepted Answer

Binding of specific proteins to mRNA, making it unavailable for translation

Question 14

A patient has a genetic disorder caused by a mutation that changes a codon from UAU (tyrosine) to UAA (stop). What is the most likely consequence?

Accepted Answer

Translation will terminate prematurely, resulting in a truncated protein.

Question 15

Which of the following is NOT a post-translational modification?

Accepted Answer

Addition of a poly(A) tail to mRNA

Question 16

What is the significance of the N-terminus and C-terminus in a polypeptide?

Accepted Answer

The N-terminus is the start of the polypeptide chain, and the C-terminus is the end, defining the direction of synthesis.

Question 17

Which of the following equations correctly represents the charging of tRNA by aminoacyl-tRNA synthetase?

Accepted Answer

$$\mathrm{Amino~acid} + \mathrm{tRNA} + \mathrm{ATP} \rightarrow \mathrm{Aminoacyl{-}tRNA} + \mathrm{AMP} + \mathrm{PP_i}$$

Question 18

Which of the following is a direct result of RNA interference (RNAi) in eukaryotic cells?

Accepted Answer

Degradation of target mRNA or inhibition of its translation

Question 19

Which of the following best describes the process of elongation during translation?

Accepted Answer

Amino acids are added to the growing polypeptide as the ribosome moves along the mRNA towards the 3' end, requiring GTP hydrolysis.

Question 20

Which of the following is a function of chaperone proteins in post-translational regulation?

Accepted Answer

They support proper folding of polypeptides into functional proteins.

Gene Expression: The Genetic Code, Translation, and Regulation

Study Guide - Practice Questions