Role of Hydrogen Bonding and Complementary Base Pairing in Transcription
- Complementary base pairing (A pairs with U, T pairs with A, C pairs with G, G pairs with C) directs which nucleotides are added during transcription.
- Hydrogen bonding between complementary bases therefore ensures the pairing is stable and accurate.
Hydrogen Bonding Is Like Molecular Glue
- Hydrogen bonds are weak interactions that hold complementary bases together:
- $A-U$ (in RNA) and $A-T$ (in DNA) form two hydrogen bonds.
- $C-G$ pairs form three hydrogen bonds.
These bonds ensure that RNA polymerase adds the correct nucleotide to the growing RNA strand.
Analogy- Think of uracil as a temporary substitute for thymine, like using a pencil instead of a pen for a draft.
- RNA is a temporary copy, so uracil works perfectly.
Ensuring Accuracy in Transcription
- Complementary base pairing ensures that RNA polymerase adds the correct nucleotide to the growing RNA strand.
- Hydrogen bonding stabilizes the pairing between bases, allowing RNA polymerase to check each nucleotide before adding it.
- This mechanism minimizes errors, ensuring the RNA copy faithfully represents the DNA template.
- Why does RNA use uracil instead of thymine?
- How does this affect base pairing during transcription?
