Final answer:
Transcription consists of initiation, where the RNA polymerase binds to the promoter; elongation, where RNA is synthesized; termination, where the newly formed RNA is released; and in eukaryotes, post-transcriptional modifications that prepare mRNA for translation.
Step-by-step explanation:
The Four Steps of Transcription
Transcription involves the synthesis of RNA from a DNA template, which includes several critical steps. These steps are essential for the proper expression of genes and involve different components and enzymes.
Initiation
Initiation is the first step of transcription where the enzyme RNA polymerase binds to a specific region on the DNA called the promoter. This step is crucial as it determines the accurate starting point for transcription and involves unwinding of the DNA strand to allow the enzyme to read the bases.
Elongation
Following initiation, elongation occurs as RNA polymerase synthesizes a new strand of RNA by adding nucleotides that are complementary to the DNA template strand. This process continues as the enzyme moves along the DNA, synthesizing the RNA molecule.
Termination
Eventually, RNA polymerase reaches a sequence called the terminator, which signals the end of the gene. Upon termination, the transcription is completed by releasing the newly synthesized RNA strand and detaching the RNA polymerase from the DNA.
Post-transcriptional Modifications (Eukaryotes)
In eukaryotic cells, before the RNA can be used for protein synthesis, it undergoes additional processing steps such as splicing, editing, and polyadenylation. These modifications are essential for producing a mature messenger RNA (mRNA) that will be transported out of the nucleus and into the cytoplasm for translation.