OCRBiologyExam Board Revision

OCR Biology Inheritance Revision Notes

Master OCR 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 the basic units of heredity and are made up of DNA.
  • 2Alleles are different forms of a gene that can lead to variations in traits.
  • 3Dominant alleles mask the effect of recessive alleles in heterozygous individuals.
  • 4Mendel's laws of inheritance describe the patterns of inheritance for traits.
  • 5Punnett squares can be used to predict the genotypes and phenotypes of offspring.

Simple Explanation

Inheritance is how traits are passed from parents to their children through genes. Each gene can have different versions called alleles, which can be dominant or recessive. Dominant alleles can hide the effects of recessive ones, so the traits we see depend on which alleles are present. This process helps explain why children might look like one parent or have a mix of features from both parents.

Memory Trick

Remember 'DRA' for Dominant, Recessive, Alleles to recall the key concepts of inheritance.

Flashcards

Question1 / 5

What is a gene?

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Exam Questions

Describe and explain the process of inheritance in pea plants as demonstrated by Mendel. [6 marks]

6 marks
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Include key points such as dominant/recessive traits, monohybrid crosses, and ratios observed.

Explain how a Punnett square can be used to predict offspring traits. [4 marks]

4 marks
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Discuss the setup of the square, parental genotypes, and interpretation of results.

What is meant by the term 'allele'? [2 marks]

2 marks
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Define allele and provide an example.

Practice Quiz

Question 1 of 5Score: 0

What is the function of genes?

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