The process of mRNA-directed polypeptide synthesis by ribosomes is called.
The Correct Answer and Explanation is:
The process of mRNA-directed polypeptide synthesis by ribosomes is called translation.
Explanation:
Translation is a fundamental step in gene expression where the genetic information encoded in messenger RNA (mRNA) is used to synthesize a specific sequence of amino acids, forming a polypeptide or protein. This process occurs in the cytoplasm of cells and is carried out by ribosomes, which are complex molecular machines composed of ribosomal RNA and proteins.
The process begins when the small subunit of a ribosome binds to the mRNA at a specific site called the start codon, which is usually the codon AUG. This codon signals the start of the translation process and codes for the amino acid methionine. A molecule called transfer RNA (tRNA) carries methionine to the ribosome. Each tRNA has an anticodon that is complementary to the mRNA codon and ensures the correct amino acid is added to the growing polypeptide chain.
As the ribosome moves along the mRNA strand, it reads each successive codon and matches it with the appropriate tRNA carrying the correct amino acid. The amino acids are joined together by peptide bonds, forming a growing polypeptide chain. This chain continues to grow until the ribosome encounters a stop codon, such as UAA, UAG, or UGA. These codons do not code for any amino acid and instead signal the end of translation.
At this point, the newly synthesized polypeptide is released from the ribosome and can then undergo folding and other modifications to become a functional protein. Translation is essential for cell function because proteins are involved in nearly every cellular process, including structure, regulation, and catalysis of biochemical reactions. It is highly regulated to ensure proteins are produced at the right time, in the right amount, and in the correct form.
