Final answer:
Transcription is the process by which a segment of DNA is copied into mRNA, the first step in gene expression leading to protein synthesis. It is carried out by the enzyme RNA polymerase, resulting in the production of a strand of RNA that contains the coding sequence of a gene.
Step-by-step explanation:
What is Transcription?
Transcription is the process by which a specific segment of DNA is copied into RNA, particularly messenger RNA (mRNA), by the enzyme RNA polymerase. This is the first step in the expression of genes into proteins. During transcription, only one strand of DNA is used as a template to produce a complementary RNA strand. The RNA strand that is synthesized has a base sequence complementary to the part of the DNA strand that encodes a gene, including regions such as the promoter, coding sequence, and terminator. This RNA molecule includes the coding sequence of a gene, which is eventually translated into a protein. Subsequently, mRNA produced by transcription leaves the nucleus and travels to the cytoplasm, where it associates with ribosomes to undergo translation, the process by which proteins are synthesized.
There are three main types of RNA produced by transcription: mRNA, transfer RNA (tRNA), and ribosomal RNA (rRNA). Only the mRNA is directly involved in protein synthesis, while tRNA and rRNA play supportive roles in translation. The transcription process is essential for the expression of the genetic information of an organism, allowing for the production of the necessary proteins to maintain life and growth.