Q: Which of the following equations correctly represents the directionality of translation?

$$\text{Ribosome moves along mRNA from 5' \rightarrow 3'}$$

Question 1

Which of the following statements best describes the role of the Shine–Dalgarno sequence in bacterial translation initiation?

Accepted Answer

It is a purine-rich sequence that aligns the start codon with the P site of the ribosome by base pairing with the 16S rRNA.

Question 2

During translation elongation, which ribosomal site is responsible for holding the tRNA carrying the growing polypeptide chain?

Accepted Answer

P site

Question 3

Which equation correctly represents the formation of a peptide bond between two amino acids?

Accepted Answer

$$\mathrm{R^1${-}CH(NH_2$){-}COOH} + \mathrm{R^2${-}CH(NH_2$){-}COOH} \rightarrow \mathrm{R^1${-}CH(NH_2$){-}CO{-}NH{-}CH(R^2$){-}COOH} + \mathrm{H_2O}$$

Question 4

Which of the following is TRUE regarding the third-base wobble in tRNA anticodon-codon pairing?

Accepted Answer

It allows a single tRNA to recognize multiple codons for the same amino acid due to flexible pairing at the third position.

Question 5

In eukaryotic translation initiation, what is the function of the Kozak sequence?

Accepted Answer

It defines the consensus sequence surrounding the start codon, facilitating recognition by the ribosome.

Question 6

Which of the following best describes the difference between monocistronic and polycistronic mRNA?

Accepted Answer

Monocistronic mRNA directs synthesis of a single polypeptide, while polycistronic mRNA directs synthesis of multiple polypeptides from one transcript.

Question 7

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

Accepted Answer

Synthesizing mRNA from DNA

Question 8

A mutation changes the third base of a codon from U to C. According to the genetic code and wobble rules, what is the most likely effect?

Accepted Answer

The tRNA may still recognize the codon due to third-base wobble, so the amino acid may remain the same.

Question 9

Which of the following equations correctly represents the directionality of translation?

Accepted Answer

$$	ext{Ribosome moves along mRNA from 5' ightarrow 3'}$$

Question 10

Which of the following statements about aminoacyl-tRNA synthetase is correct?

Accepted Answer

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

Question 11

Which of the following is a consequence of the redundancy of the genetic code?

Accepted Answer

Most amino acids are specified by multiple codons, called synonymous codons.

Question 12

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

Accepted Answer

Eukaryotic mRNAs must be exported from the nucleus to the cytoplasm for translation, while bacteria lack a nucleus.

Question 13

Which of the following is the correct sequence of events during bacterial translation initiation?

Accepted Answer

Small subunit binds mRNA, recognizes Shine–Dalgarno sequence, initiator tRNA binds start codon, large subunit joins.

Question 14

Which of the following equations represents the hydrolysis of GTP during translation initiation?

Accepted Answer

$$\mathrm{GTP} \rightarrow \mathrm{GDP} + \mathrm{P_i}$$

Question 15

Which of the following is TRUE about the structure of amino acids?

Accepted Answer

All amino acids have a central carbon, an amino group, a carboxyl group, and a unique R group.

Question 16

Which of the following statements about polyribosomes is correct?

Accepted Answer

Polyribosomes are groups of ribosomes all actively translating the same mRNA.

Question 17

Which of the following is the correct order of polypeptide structure levels?

Accepted Answer

Primary, secondary, tertiary, quaternary

Question 18

Which of the following statements about translation termination is correct?

Accepted Answer

Termination occurs when a stop codon enters the A site and a release factor binds, causing the polypeptide to be released.

Translation: The Molecular Biology of Protein Synthesis

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