What shape is DNA?
Reveal answer
A double helix.
Key words: double helix
4(b) INHERITANCE · RECALL
4.16B DNA structure
18 recall questions · Biology only (B): not in Science (Double Award). Answer from memory, reveal the answer, then rate yourself. Ratings stay on this device.
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What are the base pairs in DNA?
Reveal answer
A–T and C–G.
Key words: A · T
What is the monomer of DNA?
Reveal answer
A nucleotide (phosphate, sugar, base).
Key words: nucleotide
What bonds hold the DNA strands together?
Reveal answer
Hydrogen bonds between bases.
Key words: hydrogen
How is DNA extracted?
Reveal answer
Detergent + salt break membranes → filter → cold ethanol → DNA strands.
Key words: ethanol
Why is base pairing complementary?
Reveal answer
A with T, C with G → one strand fixes the other.
Key words: complementary
What is meant by the term nucleotide?
Reveal answer
Sugar, phosphate and nitrogenous base unit of DNA or RNA.
Key words: nucleotide
What is meant by the term double helix?
Reveal answer
Twisted structure formed by two DNA strands.
Key words: double helix
What is meant by the term complementary base pairing?
Reveal answer
Specific pairing of A with T and C with G in DNA.
Key words: complementary base pairing
What is meant by the term antiparallel?
Reveal answer
Running in opposite chemical directions.
Key words: antiparallel
DNA structural components: for Sugar-phosphate backbone, give the structure and the role.
Reveal answer
Structure: Covalently linked chain. Role: Stable outer framework.
Key words: Sugar-phosphate backbone
DNA structural components: for Base sequence, give the structure and the role.
Reveal answer
Structure: Order of A, T, C and G. Role: Stores genetic information.
Key words: Base sequence
DNA structural components: for A–T pair, give the structure and the role.
Reveal answer
Structure: Complementary bases. Role: Links opposite strands.
Key words: A–T pair
DNA structural components: for C–G pair, give the structure and the role.
Reveal answer
Structure: Complementary bases. Role: Links opposite strands.
Key words: C–G pair
DNA structural components: for Double helix, give the structure and the role.
Reveal answer
Structure: Two twisted antiparallel strands. Role: Compact, copyable information store.
Key words: Double helix
True or false, and why? “DNA contains amino acids.”
Reveal answer
False. DNA contains nucleotides; proteins contain amino acids.
True or false, and why? “A can pair with any base.”
Reveal answer
False. In ordinary DNA, A pairs with T and C with G.
True or false, and why? “Hydrogen bonds form the sugar-phosphate backbone.”
Reveal answer
False. Strong covalent bonds form the backbone; hydrogen bonds join paired bases.