gen-define-gene-transcription-and-give-one-short-worked-example-81d6

Define gene transcription and give one short worked example.

# Gene Transcription **Definition:** Gene transcription is the process by which genetic information stored in a DNA sequence is copied into a complementary RNA molecule (usually mRNA) by the enzyme RNA polymerase. ## Key Steps: 1. **Initiation** - RNA polymerase binds to the promoter region of DNA 2. **Elongation** - RNA polymerase reads the DNA template strand (3' to 5') and synthesizes RNA (5' to 3') 3. **Termination** - RNA polymerase reaches a termination signal and releases the RNA transcript --- ## Worked Example **DNA template strand (3' to 5'):** ``` 3' - TAC GGA CTT - 5' ``` **Step 1:** RNA polymerase binds and unwinds the DNA **Step 2:** RNA polymerase reads the template strand and adds complementary RNA nucleotides: - DNA: T → RNA: A - DNA: A → RNA: U (uracil replaces thymine in RNA) - DNA: C → RNA: G - DNA: G → RNA: C **mRNA transcript produced (5' to 3'):** ``` 5' - AUG CCU GAA - 3' ``` **Result:** This mRNA sequence can now be translated into a protein (in this case, the codon AUG codes for methionine, CCU for proline, and GAA for glutamic acid).