Q: Which of the following equations correctly represents the overall reaction catalyzed by aminoacyl-tRNA synthetase?

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

Question 1

Which of the following best describes the function of aminoacyl-tRNA synthetases during translation?

Accepted Answer

They attach amino acids to their corresponding tRNAs using ATP in a two-step reaction.

Question 2

A patient presents with darkened urine and bluish-black pigmentation of the sclera and ear cartilage. Which enzyme is most likely deficient, and what is the consequence at the molecular level?

Accepted Answer

Homogentisic acid oxidase; accumulation of homogentisic acid

Question 3

During translation in prokaryotes, what is the role of the Shine-Dalgarno sequence?

Accepted Answer

It facilitates the binding of the ribosome to the mRNA by base-pairing with the 16S rRNA.

Question 4

Which of the following statements about the wobble hypothesis is correct?

Accepted Answer

The third position of the codon can tolerate certain mismatches, allowing one tRNA to recognize multiple codons.

Question 5

Which of the following best explains why translation can begin before transcription is completed in bacteria but not in eukaryotes?

Accepted Answer

Bacteria lack a nucleus, so both processes occur in the cytoplasm, allowing coupling.

Question 6

A mutation in the gene encoding a specific aminoacyl-tRNA synthetase results in the enzyme attaching the wrong amino acid to its tRNA. What is the most likely consequence?

Accepted Answer

The resulting polypeptide may have incorrect amino acids, potentially leading to a nonfunctional protein.

Question 7

Which of the following is true regarding the initiation of translation in eukaryotes?

Accepted Answer

The ribosome scans from the 5’ cap until it finds the first AUG codon, following Kozak’s rules.

Question 8

Which of the following equations correctly represents the overall reaction catalyzed by aminoacyl-tRNA synthetase?

Accepted Answer

$$\mathrm{Amino\ acid} + \mathrm{tRNA} + \mathrm{ATP} ightarrow \mathrm{Aminoacyl	ext{-}tRNA} + \mathrm{AMP} + \mathrm{PP_i}$$

Question 9

Which ribosomal site is responsible for holding the tRNA carrying the growing polypeptide chain during elongation?

Accepted Answer

P site (Peptidyl site)

Question 10

In the context of translation termination in bacteria, which release factor recognizes both UAA and UGA stop codons?

Accepted Answer

RF2

Question 11

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

Accepted Answer

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

Question 12

Which component of the ribosome acts as the peptidyl transferase during translation elongation?

Accepted Answer

The 23S rRNA of the large subunit

Question 13

A mutation changes the third base of a codon from C to U, but the same amino acid is incorporated into the protein. Which concept explains this phenomenon?

Accepted Answer

The wobble hypothesis

Question 14

Which of the following is a direct consequence of a nonfunctional release factor in eukaryotic translation?

Accepted Answer

The polypeptide chain will not be released from the ribosome at a stop codon.

Question 15

Which of the following best describes the process of tRNA charging?

Accepted Answer

The attachment of an amino acid to its corresponding tRNA by aminoacyl-tRNA synthetase

Question 16

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

Accepted Answer

Synthesizing mRNA from DNA

Question 17

A new antibiotic is found to bind to the A site of the bacterial ribosome. What is the most likely effect of this antibiotic?

Accepted Answer

It will prevent the binding of aminoacyl-tRNA, halting elongation.

Question 18

Which of the following best explains Archibald Garrod’s contribution to genetics?

Accepted Answer

He proposed a relationship between genes and the production of specific enzymes.

Question 19

Which of the following codons is NOT a stop codon in the standard genetic code?

Accepted Answer

AUG

Question 20

During translation elongation, what is the correct order of tRNA movement through the ribosomal sites?

Accepted Answer

A site → P site → E site

Translation of mRNA: Mechanisms and Genetic Implications

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