A-Level Biology Inheritance Revision Notes
Master A-Level Biology Inheritance using simple revision notes, key facts and practice questions — all generated by AI for your exam.
Inheritance is the process by which genetic information is passed from parents to offspring. It explains how traits and characteristics are transmitted through generations, primarily through genes located on chromosomes.
Key Concepts
- 1Genes are units of heredity made up of DNA that determine specific traits.
- 2Alleles are different forms of a gene that can exist for a particular trait.
- 3Mendelian inheritance includes dominant and recessive traits, as well as concepts like homozygous and heterozygous.
- 4Punnett squares are used to predict the genotypes and phenotypes of offspring from parental crosses.
- 5Non-Mendelian inheritance includes incomplete dominance, codominance, and polygenic inheritance.
Simple Explanation
Inheritance is how parents pass on traits to their children through genes. Each gene can have different versions called alleles, which can be dominant or recessive. This means that some traits can mask others, affecting how they appear in the offspring. Understanding inheritance helps explain why children can look like one parent or have traits from both.
Memory Trick
“Remember 'A Dandy Punnett' for Dominant, Recessive, Alleles, and Punnett squares in inheritance.”
Flashcards
What is a gene?
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Exam Questions
Describe and explain the process of Mendelian inheritance. [6 marks]
6 marksView mark scheme hint▾
Define Mendelian inheritance, explain dominant and recessive traits, and provide examples of Punnett squares.
Explain how polygenic inheritance affects the phenotype of an organism. [4 marks]
4 marksView mark scheme hint▾
Discuss the role of multiple genes in determining a trait and provide examples.
What is meant by the term 'homozygous'? [2 marks]
2 marksView mark scheme hint▾
Define homozygous and provide an example of a homozygous genotype.
Practice Quiz
What is the term for different forms of a gene?
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