Practise 36 exam-style questions on Sexual and asexual reproduction for AQA GCSE Biology. Write your answer as you would in the exam and get it marked in seconds against the mark scheme, point by point, with an AI tutor on hand if you get stuck.
36 questions
2–5 marks each
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20 questions, marked as you go
Sample questions with model answers
Here are 4 of the questions in this topic, each with a model answer, an explanation of why it earns the marks and the mark scheme an examiner would use.
Question 1
3 marks
Explain why asexual reproduction can be advantageous for a farmer producing crops in a stable environment.
Model answer
Asexual reproduction produces genetically identical plants (clones) so desirable traits are preserved. It is fast and efficient, giving uniform crops and predictable yields; less need for pollinators or mates.
Explanation
Cloning plants by cuttings or tissue culture ensures a farmer gets many plants with the same, proven traits and uniform yield in a stable environment.
Fast / efficient / quicker than growing from seed / no need for pollination
1 mark
Uniform crop and predictable yields
Question 2
3 marks
Explain how a dominant allele and a recessive allele differ in expression in a heterozygote.
Model answer
In a heterozygote carrying one dominant and one recessive allele, the dominant allele's phenotype is expressed while the recessive allele is masked. The recessive phenotype appears only when two copies of the recessive allele are present.
Explanation
Dominant alleles determine phenotype in heterozygotes; recessive alleles only determine phenotype when homozygous.
Mark scheme
1 mark
Dominant allele expresses its trait in the presence of a different allele
1 mark
Recessive allele is masked in heterozygote and requires two copies to be expressed
1 mark
Heterozygote phenotype shows dominant trait
Question 3
4 marks
Draw a simple Punnett square and use it to show the possible genotypes of offspring when two heterozygous parents (Aa) are crossed for a single gene. State the genotypic and phenotypic ratios.
Model answer
Punnett square: parents A a across top and side; offspring: AA, Aa, aA, aa. Genotypic ratio: 1 AA : 2 Aa : 1 aa. Phenotypic ratio (if A dominant): 3 dominant : 1 recessive.
Explanation
Crossing two heterozygotes gives genotypes AA, Aa, Aa, aa (1:2:1) and phenotypes 3 dominant to 1 recessive when A is dominant.
Mark scheme
2 marks
Punnett square completed correctly with AA, Aa, aA, aa
Accept Aa and aA counted together.
1 mark
Genotypic ratio 1:2:1 (AA:Aa:aa)
1 mark
Phenotypic ratio 3:1 (if A is dominant)
Accept equivalent wording.
Question 4
5 marks
A couple undergoes IVF. Outline the main steps of IVF and give one biological reason why IVF increases the chance of pregnancy for infertile couples.
Model answer
Steps: stimulate ovaries with hormones to mature multiple eggs; collect eggs; collect sperm; fertilise eggs in lab (petri dish); develop embryos for few days; implant one or more embryo(s) into uterus. Reason: IVF allows fertilisation even if there are problems with sperm reaching egg or with ovulation; multiple embryos increase chance of implantation.
Explanation
IVF retrieves eggs and fertilises them in the lab, then implants embryos into the uterus; this bypasses infertility issues and increases pregnancy chances by implanting embryos directly.
Mark scheme
1 mark
Hormonal stimulation to mature multiple eggs
1 mark
Collect eggs and collect sperm
1 mark
Fertilise eggs in laboratory (in vitro) to form embryos
1 mark
Grow embryos then implant embryo(s) into mother's uterus
1 mark
Biological reason: bypasses problems with sperm transport or fertilisation; multiple embryos raise chance of successful implantation
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