Edexcel Biology DNA Revision Notes
Master Edexcel Biology DNA using simple revision notes, key facts and practice questions — all generated by AI for your exam.
DNA, or deoxyribonucleic acid, is the hereditary material in all living organisms. It carries genetic information necessary for growth, development, and reproduction.
Key Concepts
- 1DNA is composed of nucleotides, which include a phosphate group, a sugar (deoxyribose), and a nitrogenous base.
- 2The structure of DNA is a double helix, formed by two strands of nucleotides running in opposite directions.
- 3There are four types of nitrogenous bases in DNA: adenine (A), thymine (T), cytosine (C), and guanine (G).
- 4Base pairing occurs between A-T and C-G, which is crucial for DNA replication and protein synthesis.
- 5DNA replication is semi-conservative, meaning each new DNA molecule consists of one original and one new strand.
Simple Explanation
DNA is like a recipe book for living things, containing all the instructions needed for their growth and function. It is made up of smaller units called nucleotides, which are arranged in a specific order. This order determines how proteins are made, which are essential for life. DNA has a unique shape called a double helix, resembling a twisted ladder.
Memory Trick
“Remember 'A-T and C-G' as 'Apples in Trees and Cars in Garages' to recall the base pairing rules.”
Flashcards
What does DNA stand for?
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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 the double helix structure, components of nucleotides, base pairing, and role in heredity.
Explain how DNA replication occurs. [4 marks]
4 marksView mark scheme hint▾
Discuss the roles of enzymes, the semi-conservative nature, and the process of base pairing.
What is meant by the term 'base pairing'? [2 marks]
2 marksView mark scheme hint▾
Define base pairing and mention the specific pairs (A-T, C-G).
Practice Quiz
What is the primary function of DNA?
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