Transcription
Making an RNA copy of a gene. RNA polymerase binds a promoter, unwinds the DNA and builds messenger RNA (mRNA). In RNA, uracil (U) replaces thymine (T).
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Analogy
Copying one recipe from the book onto a card you can take to the kitchen.
Example
DNA template: T A C G G TmRNA: A U G C C AU pairs with A.T is not used in RNA.
In practice
The template strand ATGC is transcribed into the mRNA UACG.
Practice
Flashcards
- Which enzyme carries out transcription?RNA polymerase.
Interview questions
- Explain how the information in a gene becomes a protein in a eukaryotic cell.
- Transcription in nucleus makes pre-mRNA
- Splicing removes introns, cap and tail added
- mRNA exits to cytoplasm
- Ribosome reads codons with tRNA
- Amino acids joined and folded
Questions people ask
How does RNA polymerase know where to start?
It recognises a promoter, a DNA sequence just before the gene. In eukaryotes, helper proteins called transcription factors bind first and then recruit the polymerase. A terminator sequence or signal at the end of the gene tells the enzyme where to stop and release the RNA.
What is the difference between DNA and RNA?
RNA is usually single-stranded, uses ribose sugar instead of deoxyribose, and has uracil in place of thymine. It is also shorter-lived. These features suit its role as a temporary working copy, while DNA is the stable long-term store of information.