Which of the following occurs during the elongation phase of translation?

• A. The ribosome moves along the mRNA, adding amino acids to the growing polypeptide chain.
• B. The ribosome assembles at the start codon of the mRNA.
• C. The polypeptide chain is released from the ribosome.
• D. The mRNA is transcribed from DNA.

Answer: (A)

Verified step by step guidance

1. Understand the process of translation, which is the synthesis of proteins from mRNA. It occurs in three main stages: initiation, elongation, and termination.
2. During the elongation phase, the ribosome moves along the mRNA strand. This movement is crucial for the addition of amino acids to the growing polypeptide chain.
3. The ribosome facilitates the binding of tRNA molecules that carry specific amino acids. Each tRNA matches with the corresponding codon on the mRNA, ensuring the correct sequence of amino acids.
4. As the ribosome moves, it catalyzes the formation of peptide bonds between the amino acids, thus elongating the polypeptide chain.
5. The elongation phase continues until the ribosome reaches a stop codon on the mRNA, signaling the end of translation and leading to the release of the completed polypeptide chain.