CCEA A2 Biology · A2 2
A2 2: Biochemistry, Genetics and Evolutionary Trends
Respiration and ATP, monohybrid and dihybrid inheritance, sex linkage, population genetics, natural selection, speciation and gene technology.
- Level
- CCEA A2
- Weighting
- 40% of A2, 24% of the full A-level
- Exam
- A2 2 written paper (2 hours)
What A2 2 covers
- Respiration, ATP and the role of coenzymes
- Monohybrid inheritance and genetic diagrams
- Dihybrid inheritance, sex linkage and gene interactions
- Population genetics, variation and natural selection
- Speciation and evolutionary trends
- Gene technology and its applications
- Kingdoms, classification and evolutionary relationships
Assessment: Written paper — structured questions plus extended response with QWC credit. The definitive content statements are published by CCEA at ccea.org.uk.
Where marks get lost
- Genetic diagrams missing parental phenotypes, gametes or the ratio line — each is a separate mark.
- Using 'survival of the fittest' instead of naming the selection pressure and differential reproductive success.
- Chi-squared answers that state a value but never compare it to the critical value at p = 0.05.
Question styles to drill
- Full genetic crosses including sex linkage, drawn out in the CCEA layout.
- Chi-squared tests: expected ratio, degrees of freedom, critical value and conclusion.
- Extended response on natural selection applied to an unfamiliar species.
Practise A2 2 now
Generate 10 CCEA-worded A2 2 questions, or photograph a written answer and get it marked in CCEA mark-scheme language.