Inheritance: GCSE Combined Science
Sexual and asexual reproduction, meiosis, DNA, genetic diagrams, inherited disorders, variation and evolution
The short version
Compare sexual and asexual reproduction, meiosis, genes and alleles, Punnett squares, inherited disorders, and natural selection.
Key idea
Grade 2–3: Asexual is one parent and the children look the same. Sexual is two parents and they look mixed.
Grade 5–6: Gametes in sexual reproduction; clones in asexual (e.g. runners, tubers, bacteria splitting).
Grade 9: I can evaluate for a named species: strawberry runners (asexual) plus flowers (sexual).
Go a bit deeper
Humans: 46 → 23 in gametes → 46 at fertilisation
Grade 2–3: Sex cells have half the chromosomes so the baby does not get a double set.
Grade 5–6: I can contrast two vs four cells and identical vs different.
Grade 9: I never write meiosis for growth. I can say crossing over / independent assortment only as “causes variation” if the mark scheme is Combined-level.
Worked example
Worked example
Grade 2–3: Asexual is one parent and the children look the same. Sexual is two parents and they look mixed. Grade 5–6: Gametes in sexual reproduction; clones in asexual (e.g. runners, tubers, bacteria splitting). Grade 9: I can evaluate for a named species: strawberry runners (asexual) plus flowers (sexual).
Lessons in this topic
- Sexual vs asexual
- Meiosis
- DNA and the genome
- Genetic diagrams
- Inherited disorders and screening
- Variation and evolution
In the app each lesson is video (when we have a real YouTube id) then intro, learn and summary steps.
What the examiner wants
Complete genetic diagrams with ratios, use key terms (genotype, heterozygous), and discuss embryo screening ethically. Do not confuse mitosis with meiosis.
Try these questions
Cover the answers and have a go first. Worked solutions are underneath.
Asexual reproduction produces offspring that are...
An advantage of sexual reproduction is...
Meiosis produces...
Why must gametes be haploid?
Common mistakes
- Meiosis does not make 46-chromosome sperm. That would double up at fertilisation to 92.
- b is not “brown because it is written second”. Recessive only shows when homozygous.
- Mutation is random. Selection is not. Mixing those two sentences loses the 4-mark story.
- Two divisions, four different haploid cells.
Answers and working
Frequently asked questions
Is GCSE Inheritance on Combined Science and Triple?
Inheritance is on Combined Science and on Triple Biology. Progress is shared in the ReviseEasy app.
Which exam board is this Inheritance page for?
The ideas are board-agnostic for AQA, Edexcel, OCR, WJEC and CCEA. Paper lengths and question numbers differ — check your specification.
Is Inheritance Foundation or Higher?
The core ideas appear on both tiers. Higher papers add extra application and some HT-only detail, marked in lessons with a Higher badge.
Learn, try, get feedback, fix the mistake
Open the stepped lesson, then the quiz with hints. Required-practical and calculation questions use the same method you will need in the paper.
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