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The differences between sexual and asexual reproduction, the structure of DNA and its role in making proteins, mutations and their effects and how characteristics are inherited.

Mutations can cause a permanent change in the DNA of an organism. In the 19th century, Gregor Mendel determined rules to explain genetic inheritance using pea plants. Genetic crosses using Punnett squares show how likely offspring are to inherit characteristics from their parents.

We inherit our sex (male or female) and blood group from our parents. Genetic disorders can also be inherited. Selective breeding occurs when humans breed plants and animals for specific characteristics. Cloning (often in plants and not in humans) makes genetically identical copies of the one parent organism.

Understanding how to approach exam questions helps to boost exam performance. Question types will include multiple choice, structured, mathematical and practical questions.