Biology A-Level
DNA double helix
What DNA double helix means in Biology A-Level, as defined for OCR.
Definition of DNA double helix
Check what you remember
Read the wording for your board, then hide it and explain DNA double helix in your own words. Rough notes are fine. This is a self-check, with no mark or grade.
Reference: OCR
Two antiparallel strands run in opposite directions and wind into a double helix, with the sugar–phosphate backbone on the outside and the paired bases on the inside.
Topics that use DNA double helix
- Nucleotides and nucleic acids (OCR A-Level)
Related terms
- ATP and ADP as energy carriers
- Codon–anticodon pairing and peptide bond formation
- Cold conditions protecting DNA and aiding precipitation
- complementary base pairing
- Complementary base pairing of free nucleotides
- Condensation polymerisation
- Conservation of one original strand per daughter molecule
- hydrolysis
Using DNA double helix in the exam
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