What is transcription with reference to protein synthesis? How does it take place?
Transcription means copying the sequence of bases from DNA on messenger RNA (m-RNA). The copying of DNA sequence into m-RNA proceeds according to the same base pairing principle as in replication but differ in the following two respects:
(i) During m-RNA synthesis, the DNA double helix structure opens up and the ribonucleotides assemble along the uncoiled strand of DNA.
(ii) The base adenine (A) in DNA strand pair up with the uracil (U) in RNA.
After transcription, the m-RNA-DNA double helix separates. The m-RNA detaches itself and migrates to cytoplasm, while the DNA returns to its double helix structure.