What is the correct order of protein synthesis?

• A. Translation then transcription
• B. Transcription then translation
• C. Replication then transcription
• D. Transcription only

Answer: (B)

The correct order of protein synthesis is transcription followed by translation. In the first step, transcription occurs in the nucleus of the cell where the DNA sequence of a gene is copied into messenger RNA (mRNA). This mRNA serves as a template that carries the genetic information from the DNA to the ribosomes, the sites of protein synthesis.

Once the mRNA is synthesized, it undergoes processing to remove introns and add a 5' cap and a poly-A tail before it's transported out of the nucleus into the cytoplasm. In the second step, translation takes place at the ribosomes. During translation, the mRNA is read in sets of three nucleotides (codons), which each specify a particular amino acid. Transfer RNA (tRNA) molecules bring the corresponding amino acids to the ribosome, where they are linked together in the order specified by the mRNA sequence, forming a polypeptide chain that will eventually fold into a functional protein.

This sequence of events is essential in cellular biology, as it illustrates how the genetic code is expressed in terms of protein production, which is crucial for the structure and function of cells and organisms. Other choices do not accurately reflect the established processes of protein synthesis; they either incorrectly imply the sequence