During protein synthesis

Options

A. Code on mRNA is translated
B. Coding is done by DNA strands
C. Code is transferred on tRNA
D. all of these are correct

Answer

**Step-by-Step Solution:**

1. **Understanding Protein Synthesis**: Protein synthesis is a crucial biological process that involves the creation of proteins from amino acids. It occurs through a series of steps known as the Central Dogma of molecular biology, which includes replication, transcription, and translation.

2. **Replication**: The first step in the Central Dogma is DNA replication. During this process, the DNA molecule makes a copy of itself. This is essential because it ensures that genetic information is passed on during cell division.

3. **Transcription**: The second step is transcription, where the DNA sequence of a gene is transcribed to produce messenger RNA (mRNA). This process involves the enzyme RNA polymerase, which binds to the DNA and synthesizes a single strand of mRNA based on the DNA template.

4. **Translation**: The final step is translation, where the mRNA is translated into a specific sequence of amino acids, forming a protein. This occurs in the ribosome, where transfer RNA (tRNA) molecules bring amino acids to the ribosome in accordance with the codon sequence on the mRNA.

5. **Codon Translation**: Each three-nucleotide sequence on the mRNA, known as a codon, corresponds to a specific amino acid. The ribosome reads the mRNA codons and, with the help of tRNA, assembles the amino acids in the correct order to form a protein.

6. **Evaluating Options**: Given the options in the question:
- "Code on mRNA is translated" is correct because mRNA codons are indeed translated into proteins.
- "Coding is done by DNA strands" is incorrect because DNA is used to produce mRNA, not directly code for proteins.
- "Code is transferred on tRNA" is also incorrect; tRNA carries amino acids to the ribosome based on mRNA codons, not the other way around.
- "All of these are correct" is incorrect since not all statements are true.

7. **Conclusion**: The correct statement regarding protein synthesis is that the code on mRNA is translated during the process of translation to synthesize proteins.