Final answer:
Transcription is the initial step in the synthesis of a secretory protein, involving RNA polymerase and resulting in the formation of mRNA. Option 1 is correct..
Step-by-step explanation:
During synthesis of a secretory protein, the initial step is transcription. This critical first phase occurs within the cell's nucleus and involves RNA polymerase, the enzyme that initiates the production of messenger-RNA (mRNA) based on a DNA template. Transcription follows three main steps: initiation—where the DNA molecule unwinds and RNA polymerase binds to the DNA; elongation—where RNA polymerase assembles the RNA nucleotides into a strand that is complementary to the DNA; and termination—when a termination signal is reached, causing the RNA polymerase and the newly formed mRNA strand to dissociate from the DNA.
After transcription, the mRNA exits the nucleus, and protein synthesis continues with translation in the cytoplasm. The initial step during synthesis of a secretory protein is transcription. Transcription is the process in which DNA is unraveled and a messenger RNA (mRNA) strand is produced. This step takes place in the nucleus of the cell.