AQA Biology DNA Revision Notes
Master AQA Biology DNA using simple revision notes, key facts and practice questions — all generated by AI for your exam.
DNA, or deoxyribonucleic acid, is the molecule that carries genetic information in living organisms. It is composed of two strands that coil around each other to form a double helix, with each strand made up of nucleotides containing a sugar, a phosphate group, and a nitrogenous base.
Key Concepts
- 1DNA structure consists of a double helix formed by two strands of nucleotides.
- 2Nucleotides are made up of a sugar, phosphate group, and nitrogenous base.
- 3The four nitrogenous bases in DNA are adenine (A), thymine (T), cytosine (C), and guanine (G).
- 4Base pairing occurs specifically between A-T and C-G, ensuring accurate DNA replication.
- 5DNA is organized into genes, which code for proteins and determine traits.
Simple Explanation
DNA is like a recipe book for living things, containing all the instructions needed for growth and function. It is made up of smaller units called nucleotides, which include a sugar, a phosphate, and a base. The bases pair up in a specific way to form the structure of DNA, allowing it to replicate and pass on genetic information. Genes, which are segments of DNA, tell our cells how to make proteins that perform various functions in our bodies.
Memory Trick
“Remember 'A-T, C-G' as 'Apples in Trees, Cars in Garages' to recall the base pairing rules in DNA.”
Flashcards
What are the components of a nucleotide?
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Exam Questions
Describe and explain the structure of DNA and its significance in heredity. [6 marks]
6 marksView mark scheme hint▾
Mention double helix structure, nucleotides, base pairing, and role in inheritance.
Explain how DNA replication occurs. [4 marks]
4 marksView mark scheme hint▾
Include the role of enzymes, unwinding, and base pairing.
What is meant by the term 'gene'? [2 marks]
2 marksView mark scheme hint▾
Define gene and its function in coding for proteins.
Practice Quiz
What is the primary function of DNA?
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