This exam focus covers Exam Focus within Inherited Disorders for GCSE Biology. Genetic disorders, family pedigrees, and probability calculations It is section 9 of 11 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Topic position
Section 9 of 11
Practice
25 questions
Recall
20 flashcards
Exam Focus
Frequently ExaminedInherited disorders are a core AQA topic and appear in almost every Paper 2. Common question formats:
- Punnett square with probability: Carrier x carrier cross (Ff x Ff), state probability of affected child as fraction and percentage.
- Explain questions: "Explain why a child can have CF even though both parents are healthy." Requires: carrier definition, recessive allele needs two copies, Punnett square evidence.
- Compare CF and polydactyly: Be clear that CF is recessive (both parents must be carriers) and polydactyly is dominant (one affected parent is enough).
- Evaluate genetic screening: 4-6 mark questions ask you to weigh benefits vs ethical concerns. Include both scientific (disease prevention) and ethical (autonomy, discrimination) arguments.
Key distinction to memorise: CF = recessive (ff), polydactyly = dominant (P). This is almost always tested as a "state which type is recessive/dominant" question.