Question 1

Which of the following statements best describes the main difference between prokaryotic and eukaryotic mRNA processing?

Accepted Answer

Eukaryotic mRNAs undergo capping, polyadenylation, and splicing, while prokaryotic mRNAs do not.

Question 2

Which enzyme is responsible for the conversion of cytidine to uridine during RNA editing of the human APO-B gene in the intestine?

Accepted Answer

Cytidine deaminase

Question 3

Which codon serves as the universal start codon for translation in both prokaryotes and eukaryotes?

Accepted Answer

$$\mathrm{AUG}$$

Question 4

A patient presents with easy bruising and poor wound healing. Laboratory tests reveal a deficiency in vitamin C. Which post-translational modification is most likely impaired?

Accepted Answer

Hydroxylation of proline and lysine residues in collagen

Question 5

Which of the following antibiotics inhibits protein synthesis by binding irreversibly to the 30S ribosomal subunit and causing misreading of mRNA?

Accepted Answer

Streptomycin

Question 6

Which of the following is a function of small nuclear RNA (snRNA)?

Accepted Answer

Splicing of pre-mRNA

Question 7

Which of the following post-translational modifications is vitamin K dependent and is inhibited by warfarin?

Accepted Answer

Carboxylation of glutamate residues

Question 8

Which of the following best describes the direction of RNA synthesis during transcription?

Accepted Answer

5' to 3' direction

Question 9

A mutation in the gene encoding lysyl hydroxylase leads to which type of Ehlers-Danlos Syndrome (EDS)?

Accepted Answer

Kyphoscoliosis type (EDS VI)

Question 10

Which of the following statements about the genetic code is correct?

Accepted Answer

The code is degenerate, meaning most amino acids are specified by more than one codon.

Question 11

Which eukaryotic RNA polymerase is responsible for synthesizing tRNA?

Accepted Answer

RNA polymerase III

Question 12

Which of the following best explains why prokaryotic transcription and translation are coupled?

Accepted Answer

Prokaryotes lack a nuclear membrane, allowing ribosomes to access mRNA as it is being transcribed.

Question 13

Which of the following is a unique feature of mitochondrial genetic code compared to the universal genetic code?

Accepted Answer

$$\mathrm{UGA}$$ codes for tryptophan instead of stop.

Question 14

Which of the following antibiotics causes premature chain termination by mimicking the 3' end of aminoacyl-tRNA?

Accepted Answer

Puromycin

Question 15

A patient with chronic lung and liver disease is found to have a deficiency in a serine protease inhibitor that protects tissues from elastase. Which protein is deficient?

Accepted Answer

α1-antitrypsin

Question 16

Which of the following is a function of the 5' cap added to eukaryotic mRNA?

Accepted Answer

Protects mRNA from degradation by RNases

Question 17

Which of the following post-translational modifications is required for the activation of blood clotting factors II, VII, IX, and X?

Accepted Answer

γ-carboxylation of glutamate residues

Question 18

Which of the following is true regarding the structure of tRNA?

Accepted Answer

The 3' terminus contains the sequence CCA, which is the site of amino acid attachment.

RNA and Protein Synthesis: Structure, Function, and Regulation

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