Answer:
e) A large complex consisting of RNA polymerase and other proteins assembles on the DNA strand.
d) The DNA is unwound and a specific sequence of nucleotides is sequenced along the promoter.
a) RNA polymerase uses the DNA strand as a template to synthesize a complementary strand of RNA.
b) The RNA strand grows until an entire gene has been transcribed.
c) The complex of RNA polymerase and proteins breaks apart.
Explanation:
The two major processes that occur in the cells of an organism during protein synthesis are transcription (DNA to RNA) and translation (RNA to protein).
Transcription, the first process in protein synthesis occurs in the nucleus of the cell where a single-stranded messenger RNA (mRNA) is synthesized using a DNA strand. The genetic instructions in DNA are transferred to this mRNA. Various steps in transcription include initiation, elongation, and termination.
Initiation, the starting process occurs when a complex consisting of a group of proteins called transcription factors and an enzyme RNA polymerase assembles on the DNA strand. The RNA polymerase binds to a promoter (region of a gene) and the DNA unwinds. One of the DNA strands acts as a template and the enzyme reads the bases in the template DNA strand. In the next step called elongation, the RNA polymerase synthesizes a strand of mRNA by the addition of nucleotides using complementary base pairs. Here, adenine (A) in the DNA binds to uracil (U) in the RNA. The RNA strand grows until the entire genetic instructions in DNA have been transcribed. During the last step called termination, the RNA polymerase comes across a termination sequence in the gene. The RNA polymerase-protein complex breaks apart and the transcription process ends. Thus, the completed single-stranded mRNA detaches from DNA.
Translation, the second process in protein synthesis takes place in the ribosome of the cell where the genetic information transcribed to mRNA is decoded and used to create a protein from amino acids.
