EdexcelBiologyExam Board Revision

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 molecule that carries the genetic instructions for life. It is composed of two strands that coil around each other to form a double helix. DNA is essential for the replication of cells and the transmission of genetic information from one generation to the next.

Key Concepts

  • 1DNA structure consists of nucleotides made of a sugar, phosphate group, and nitrogenous base.
  • 2The four nitrogenous bases in DNA are adenine (A), thymine (T), cytosine (C), and guanine (G).
  • 3Base pairing occurs between A-T and C-G, which is crucial for DNA replication.
  • 4DNA replication is semi-conservative, meaning each new DNA molecule contains one original and one new strand.
  • 5Mutations can occur in DNA, leading to changes in the genetic code, which may affect protein synthesis.

Simple Explanation

DNA is like a recipe book for living things, containing instructions on how to build and operate an organism. It is made of smaller units called nucleotides, which have a sugar, a phosphate, and a base. The bases pair up in a specific way to form the double helix structure. When cells divide, DNA is copied so that each new cell has the same instructions.

Memory Trick

“Remember 'A-T, C-G' as 'Apples in Trees, Cars in Garages' to recall the base pairing rules of DNA.”

Flashcards

Question1 / 5

What are the building blocks of DNA?

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Exam Questions

Describe and explain the structure of DNA and its significance in genetics. [6 marks]

6 marks
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Include details on the double helix structure, nucleotide composition, base pairing, and the role of DNA in heredity.

Explain how DNA replication occurs, including the role of enzymes. [4 marks]

4 marks
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Mention the unwinding of the double helix, base pairing, and the function of DNA polymerase.

What is meant by a mutation in DNA? [2 marks]

2 marks
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Define mutation and provide an example of its potential effects on an organism.

Practice Quiz

Question 1 of 5Score: 0

What is the primary function of DNA?

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