What is the process of protein synthesis from DNA to functional protein?

• A. DNA is synthesized into mRNA in the cytoplasm
• B. RNA is translated into DNA in the nucleus
• C. DNA is transcribed in the nucleus followed by mRNA translation by ribosomes
• D. mRNA is stored and later converted into proteins

Answer: (C)

The process of protein synthesis begins with DNA transcribing into messenger RNA (mRNA) within the nucleus. This transcription involves the enzyme RNA polymerase, which reads the DNA template and synthesizes a complementary strand of mRNA. Once the mRNA is formed, it undergoes several modifications, including splicing and the addition of a 5' cap and poly-A tail, which prepares it for export from the nucleus into the cytoplasm.

Once in the cytoplasm, the mRNA serves as a template for translation, where ribosomes read the mRNA sequence and assemble the corresponding amino acids into a polypeptide chain, ultimately folding into a functional protein. This sequence of transcription followed by translation is fundamental to the central dogma of molecular biology, illustrating how genetic information flows from DNA to protein.

The other options misrepresent the established processes of molecular biology. For instance, the idea that RNA is translated back into DNA or that mRNA is simply stored without being used for protein synthesis contradicts the flow of genetic information. Understanding this order and function is crucial for grasping how proteins are ultimately created from genetic instructions.