Translation elongation

Definition

Translation elongation is the phase of protein synthesis where amino acids are sequentially added to a growing polypeptide chain. During this process, transfer RNA (tRNA) molecules play a crucial role by bringing specific amino acids to the ribosome, where they are linked together according to the sequence dictated by messenger RNA (mRNA). This stage is essential for building proteins that perform various functions in the cell.

5 Must Know Facts For Your Next Test

1. During translation elongation, the ribosome moves along the mRNA in the 5' to 3' direction, adding amino acids one by one to the growing polypeptide chain.
2. Each cycle of elongation involves the entry of an aminoacyl-tRNA into the A site of the ribosome, peptide bond formation in the P site, and translocation of the ribosome.
3. Elongation factors are proteins that assist in various steps of translation elongation, including promoting tRNA binding and facilitating ribosomal movement along mRNA.
4. The duration of translation elongation can vary depending on factors such as the speed of tRNA delivery and the complexity of the protein being synthesized.
5. Translation elongation continues until a stop codon on the mRNA is reached, signaling the termination phase where the completed polypeptide is released.

Review Questions

• How does translation elongation contribute to the overall process of protein synthesis?
  • Translation elongation is a vital step in protein synthesis as it involves adding amino acids to form a polypeptide chain. This process occurs after initiation and sets up the ribosome to continuously add amino acids according to the mRNA sequence. By efficiently extending the chain, translation elongation ensures that proteins are synthesized accurately and promptly to perform their cellular functions.
• Discuss the role of tRNA and ribosomes in translation elongation and how they work together to synthesize proteins.
  • In translation elongation, tRNA molecules transport specific amino acids to the ribosome, where their anticodons base-pair with corresponding codons on the mRNA. The ribosome provides a platform for this interaction and catalyzes peptide bond formation between amino acids. This teamwork allows for precise protein synthesis as tRNAs ensure that each amino acid is added in accordance with the genetic code carried by mRNA.
• Evaluate how changes in translation elongation efficiency could impact cellular functions and organismal health.
  • Changes in translation elongation efficiency can have significant implications for cellular functions and overall health. If elongation occurs too slowly, proteins may not be produced at adequate levels, leading to deficiencies that could impair cell function or response to stress. Conversely, if elongation happens too quickly without proper quality control, misfolded or malfunctioning proteins may be produced, potentially resulting in diseases such as cancer or neurodegenerative disorders. Thus, maintaining a balanced rate of translation elongation is critical for cellular homeostasis and organismal health.

Related terms

tRNA:

Transfer RNA (tRNA) is a type of RNA that carries amino acids to the ribosome during protein synthesis, matching its anticodon with codons on the mRNA.

Ribosome: The ribosome is a molecular machine made of ribosomal RNA (rRNA) and proteins that facilitates the translation of mRNA into a polypeptide chain.

Peptidyl transferase: Peptidyl transferase is an enzymatic activity within the ribosome that catalyzes the formation of peptide bonds between adjacent amino acids during translation.