Final answer:
Transcription is the process where an RNA Polymerase enzyme creates an mRNA strand complementary to the DNA template strand, with Uracil (U) replacing Thymine (T). This mRNA strand will be processed and then used in protein synthesis.
Step-by-step explanation:
The process of copying a nucleotide sequence of DNA to form a complementary strand of mRNA is known as transcription. This process consists of several steps:
- Initiation: Transcription begins when the enzyme RNA Polymerase binds to the promoter region of a gene and unwinds a small portion of the DNA double helix, exposing the template strand.
- Elongation: RNA Polymerase reads the DNA template strand and synthesizes the mRNA strand by adding RNA nucleotides that are complementary to the template strand. Adenine (A) pairs with Uracil (U) in mRNA, Cytosine (C) pairs with Guanine (G), and vice versa.
- Termination: Once the entire gene is transcribed, the RNA strand detaches, and the DNA helix re-forms. In eukaryotes, this newly formed mRNA may undergo further processing before it leaves the nucleus.
As a result, the mRNA sequence is complementary to the DNA template strand, except uracil replaces thymine. This mRNA will later be used during translation to synthesize a protein.