Which of the following contribute in polypeptide synthesis?
**Core Concept**
Polypeptide synthesis refers to the process of forming proteins from amino acids, which is crucial for various cellular functions, including enzyme activity, structural support, and immune response. This process involves the translation of messenger RNA (mRNA) into a sequence of amino acids. The key enzymes and molecules involved in this process are ribosomes, transfer RNA (tRNA), and aminoacyl-tRNA synthetases.
**Why the Correct Answer is Right**
The correct answer is **tRNA**. Transfer RNA (tRNA) plays a vital role in polypeptide synthesis by bringing the correct amino acid to the ribosome during translation. tRNA molecules are charged with the corresponding amino acid by aminoacyl-tRNA synthetases, which link the amino acid to the tRNA molecule. The charged tRNA then binds to the ribosome, where it is positioned for peptide bond formation. This process is essential for the accurate assembly of amino acids into a polypeptide chain.
**Why Each Wrong Option is Incorrect**
* **Option A:** Ribosomes are involved in the process of polypeptide synthesis, but they are not the direct contributors to bringing the amino acids to the translation site.
* **Option B:** Aminoacyl-tRNA synthetases are involved in charging tRNA with the correct amino acid, but they are not the direct contributors to polypeptide synthesis.
* **Option D:** mRNA is involved in the process of translation, but it is not a direct contributor to polypeptide synthesis, as it provides the sequence information for the polypeptide chain.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that genetic mutations affecting tRNA or aminoacyl-tRNA synthetases can lead to amino acid misincorporation into proteins, resulting in various diseases, including some forms of cancer and neurological disorders.
**Correct Answer:** C.