Lesson 4.6.1.4

4.6.1.4 Genetic inheritance Quiz: AQA Combined Science, Unit 6

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.6.1.4, Genetic inheritance: 20 multiple choice questions for the AQA GCSE Combined Science (8464), Unit 6: Inheritance, variation and evolution, written with Revision Ninja.

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The 20 questions

  1. What is the biological term for a sex cell?

    • Embryo
    • Zygote
    • Gamete
    • Genome

  2. What is the term for alternative forms of the same gene?

    • Gametes
    • Chromosomes
    • Genotypes
    • Alleles

  3. Which type of allele is always expressed if present?

    • Dominant allele
    • Mutated allele
    • Recessive allele
    • Heterozygous allele

  4. How many copies of a recessive allele must be present for it to be expressed?

    • Two copies
    • Four copies
    • Three copies
    • One copy

  5. What term describes having two identical alleles for a trait?

    • Homozygous
    • Heterozygous
    • Recessive
    • Dominant

  6. What term describes having two different alleles for a trait?

    • Heterozygous
    • Homozygous
    • Recessive
    • Purebred

  7. Which term refers to the combination of alleles an organism carries?

    • Phenotype ratio
    • Phenotype
    • Genotype
    • Gamete

  8. Which term describes observable characteristics such as eye colour?

    • Phenotype
    • Allele
    • Gamete
    • Genotype

  9. A person has brown eyes (B dominant) and genotype Bb. What eye colour is expected?

    • Brown
    • Blue
    • Neither colour
    • Both colours equally

  10. A cross of Bb with bb is performed. What is the probability of a blue-eyed offspring?

    • 3 in 4 (75%)
    • 1 in 4 (25%)
    • 0%
    • 1 in 2 (50%)

  11. What proportion of offspring from a Bb by Bb cross show the dominant phenotype?

    • 1 in 2 (50%)
    • 1 in 4 (25%)
    • 3 in 4 (75%)
    • 1 in 3 (33%)

  12. What is the genotype ratio from a Bb by Bb cross?

    • 1:2:1
    • 1:1
    • 1:1:1:1
    • 3:1

  13. Fur colour in mice is controlled by a single gene. A mouse has two copies of the same allele. Which term describes this?

    • Recessive gamete
    • Heterozygous
    • Homozygous
    • Dominant only

  14. If a child shows a recessive trait from parents who do not, what are the parents?

    • Homozygous recessive
    • Heterozygous carriers
    • Homozygous dominant
    • Cloned mutants

  15. What does a 25% probability of a recessive offspring in a genetic cross mean?

    • Guaranteed inheritance
    • Probability per child
    • Total sterile rate
    • Exact family outcome

  16. How are most phenotypic characteristics controlled in organisms?

    • Single dominant genes
    • Environmental triggers only
    • Single recessive genes
    • Multiple interacting genes

  17. Why do most human phenotypes fail to follow simple Mendelian ratios?

    • Single gene control
    • Constant mutation rates
    • Lack of alleles
    • Multiple gene interaction

  18. Two parents are both heterozygous for a recessive trait. What is the probability a child is homozygous recessive?

    • 1 in 4
    • 1 in 2
    • 1 in 8
    • 3 in 4

  19. Two parents are both heterozygous for a dominant trait. What is the probability a child is heterozygous?

    • 3 in 4
    • 1 in 8
    • 1 in 2
    • 1 in 4

  20. How can a recessive allele remain hidden across generations?

    • Heterozygous masking
    • Immediate mutation
    • Dominant suppression
    • Cellular destruction

All AQA Combined Science quizzes