Termination of chain growth in protein syntesis is brough about by-

Options

A. UUU, UGC, UCA
B. UCG, GCG, ACC
C. UAA, UAG, UGA
D. UUG, UAG, UCG

Answer

**Step-by-Step Solution:**

1. **Understanding Codons**: Codons are sequences of three nucleotides in mRNA that correspond to specific amino acids. Each codon is responsible for coding one amino acid during protein synthesis.

2. **Start Codon**: The process of protein synthesis begins with a start codon. The most common start codon is AUG, which codes for the amino acid methionine (MET). This marks the beginning of translation.

3. **Role of tRNA**: Transfer RNA (tRNA) plays a crucial role in translation by reading the codons on the mRNA and bringing the corresponding amino acids to form a growing polypeptide chain.

4. **Termination of Translation**: The process of translation does not continue indefinitely; it must eventually stop. This termination is signaled by specific codons known as stop codons.

5. **Stop Codons**: Stop codons do not code for any amino acids. The three stop codons are UAA, UAG, and UGA. When the ribosome encounters any of these codons during translation, it signals the end of protein synthesis.

6. **Release of Protein**: Upon reaching a stop codon, the tRNA does not bring any amino acid, and the polypeptide chain is released, completing the process of protein synthesis.

**Final Answer**: The termination of chain growth in protein synthesis is brought about by the stop codons UAA, UAG, or UGA.

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