Question

1. this is the first step in this process when the first trna enters the p site and the second trna enters the a site on the complexed ribosome and mrna strand at a start codon (aug).

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first translocation; trna 2 shifts into p site; entrance of trna 3
process repeated until stop codon is reached
entrance of trnas 1 and 2
discharge of trna 1 at the e site
formation of peptide bond
discharge of trna 2; second translocation; enter trna 4

1. this is the fourth step in this process when the ribosome moves along the mrna strand by 3 bases (a codon).

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1. this is the fifth step in this process when another condensation reaction brings together the molecules bound to two trna molecules.

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1. this is the sixth step in this process when the ribosome again moves along the mrna strand by 3 bases (a codon).

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1. this is the seventh step in this process when a third amino acid is added to the growing polypeptide chain.

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1. the final step in this process is termination when the ribosome reaches a stop codon on the mrna strand.

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Explanation:

Analyze translation steps 1 to 3

The first step describes the initial assembly where tRNA 1 (initiator tRNA) enters the P site and tRNA 2 enters the A site at the start codon. This corresponds to "Entrance of tRNAs 1 and 2".
The second step (partially visible behind the dropdown) describes the condensation reaction forming a peptide bond between the amino acids on the two tRNAs. This corresponds to "Formation of peptide bond".
The third step describes tRNA 1 leaving the ribosome via the exit (E) site. This corresponds to "Discharge of tRNA 1 at the E site".

Analyze translation steps 4 to 6

The fourth step describes the ribosome moving along the mRNA strand by 3 bases (one codon). This is the first translocation event where tRNA 2 shifts into the P site and tRNA 3 enters the A site. This corresponds to "First translocation; tRNA 2 shifts into P site; entrance of tRNA 3".
The fifth step describes another condensation reaction forming a peptide bond. This corresponds to "Formation of peptide bond".
The sixth step describes the ribosome moving again by 3 bases, which is the second translocation accompanied by the discharge of tRNA 2 and entrance of tRNA 4. This corresponds to "Discharge of tRNA 2; second translocation; enter tRNA 4".

Analyze translation steps 7 and 8

The seventh step describes a third amino acid being added to the growing polypeptide chain, which is a repeated cycle of elongation. This corresponds to "Formation of peptide bond".
The eighth step describes the final step of termination when a stop codon is reached. This corresponds to "Process repeated until stop codon is reached".

Answer:

Question 1

• First translocation; tRNA 2 shifts into P site; entrance of tRNA 3
• Process repeated until stop codon is reached
• Entrance of tRNAs 1 and 2 (Correct answer)
• Discharge of tRNA 1 at the E site
• Formation of peptide bond
• Discharge of tRNA 2; second translocation; enter tRNA 4

Question 2

• First translocation; tRNA 2 shifts into P site; entrance of tRNA 3
• Process repeated until stop codon is reached
• Entrance of tRNAs 1 and 2
• Discharge of tRNA 1 at the E site</mcq-correct>
• Formation of peptide bond (Correct answer)

<mcq-option>Discharge of tRNA 2; second translocation; enter tRNA 4

Question 3

• First translocation; tRNA 2 shifts into P site; entrance of tRNA 3
• Process repeated until stop codon is reached
• Entrance of tRNAs 1 and 2
• Discharge of tRNA 1 at the E site (Correct answer)
• Formation of peptide bond
• Discharge of tRNA 2; second translocation; enter tRNA 4

Question 4

• First translocation; tRNA 2 shifts into P site; entrance of tRNA 3 (Correct answer)
• Process repeated until stop codon is reached
• Entrance of tRNAs 1 and 2
• Discharge of tRNA 1 at the E site
• Formation of peptide bond
• Discharge of tRNA 2; second translocation; enter tRNA 4

Question 5

• First translocation; tRNA 2 shifts into P site; entrance of tRNA 3
• Process repeated until stop codon is reached
• Entrance of tRNAs 1 and 2
• Discharge of tRNA 1 at the E site
• Formation of peptide bond (Correct answer)
• Discharge of tRNA 2; second translocation; enter tRNA 4

Question 6

• First translocation; tRNA 2 shifts into P site; entrance of tRNA 3
• Process repeated until stop codon is reached
• Entrance of tRNAs 1 and 2
• Discharge of tRNA 1 at the E site
• Formation of peptide bond
• Discharge of tRNA 2; second translocation; enter tRNA 4 (Correct answer)

Question 7

• First translocation; tRNA 2 shifts into P site; entrance of tRNA 3
• Process repeated until stop codon is reached
• Entrance of tRNAs 1 and 2
• Discharge of tRNA 1 at the E site
• Formation of peptide bond (Correct answer)
• Discharge of tRNA 2; second translocation; enter tRNA 4

Question 8

• First translocation; tRNA 2 shifts into P site; entrance of tRNA 3
• Process repeated until stop codon is reached (Correct answer)
• Entrance of tRNAs 1 and 2
• Discharge of tRNA 1 at the E site
• Formation of peptide bond
• Discharge of tRNA 2; second translocation; enter tRNA 4