Edexcel A Level Biology A (Salters-Nuffield)
Edexcel A Level Biology A (Salters-Nuffield) Topic 2: Inheritance, Cystic Fibrosis and Screening Exam Questions
Free Edexcel A Level Biology A (Salters-Nuffield) exam questions on Topic 2: Inheritance, Cystic Fibrosis and Screening, with mark schemes. Covers gene mutations, monohybrid inheritance, cystic fibrosis, genetic screening and ethics.
Topic 2: Inheritance, Cystic Fibrosis and Screening exam questions
These packs of real past exam questions cover the whole of Topic 2: Genes and Health, including Topic 2: Inheritance, Cystic Fibrosis and Screening. Work through every question on this sub-topic, then mark your answers against the mark scheme.
StemUp mark scheme flashcards
Edexcel A Level Biology A (SNAB) 9BN0 Flashcards (Anki & Quizlet)
Every answer is written in mark scheme wording, so you learn exactly what examiners give marks for. Use them on Anki or Quizlet, then test yourself with the questions on this page.
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About Edexcel A Level Biology A (Salters-Nuffield) Topic 2: Inheritance, Cystic Fibrosis and Screening
This part of Topic 2 applies genetics to a real disease. Expect genetic diagrams, probability questions and ethical evaluation of screening.
What you need to know
- Mutations A change in the DNA base sequence can change the amino acid sequence and the protein.
- Monohybrid inheritance Genotype, phenotype, dominant, recessive, homozygous, heterozygous, and genetic diagrams with probabilities.
- Cystic fibrosis A recessive mutation in the CFTR gene leads to thick mucus affecting the lungs, pancreas and reproductive system.
- Genetic screening Preimplantation genetic diagnosis, prenatal testing (amniocentesis, chorionic villus sampling) and the ethical issues raised.
Common mistakes in Topic 2: Inheritance, Cystic Fibrosis and Screening
- Using capital and lower case letters inconsistently in genetic diagrams.
- Giving probability as a ratio when a percentage or fraction is asked for.
- Writing about ethics without balanced arguments.
Try three Topic 2: Inheritance, Cystic Fibrosis and Screening exam-style questions
1. Two carriers of cystic fibrosis have a child. Give the probability the child has CF. (1 mark)
Show the mark scheme answer
0.25 (1 in 4 or 25 percent).
2. Explain how a mutation in the CFTR gene causes thick mucus. (3 marks)
Show the mark scheme answer
The mutation changes the amino acid sequence so the CFTR protein is faulty (1). Chloride ions are not transported out of cells (1), so less water leaves by osmosis and mucus stays thick and sticky (1).
3. Give one ethical issue with prenatal genetic testing. (1 mark)
Show the mark scheme answer
Any one: risk of miscarriage, decisions about termination, who decides what conditions to test for.
Topic 2: Inheritance, Cystic Fibrosis and Screening FAQs
What does this part of SNAB Topic 2 cover?
Mutation, monohybrid inheritance, cystic fibrosis and genetic screening.
Do I need genetic diagrams?
Yes, with parental genotypes, gametes, offspring and probabilities.
How should I answer ethics questions?
Give arguments for and against and use ethical frameworks where helpful.
Revise this topic with flashcards: Edexcel A Level Biology A (SNAB) 9BN0 Flashcards, with mark scheme answers for Anki and Quizlet.
