Lesson 3.4.3.1

3.4.3.1 Gene and chromosome mutation Quiz: AQA Biology, Unit 4

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.4.3.1, Gene and chromosome mutation: 20 multiple choice questions for the AQA Biology (7402), Unit 4: Genetic information, variation and relationships, written with Revision Ninja.

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The 20 questions

  1. What is defined as a change in the DNA base sequence of a gene?

    • Gene expression
    • Chromosome mutation
    • Gene mutation
    • Epigenetic change

  2. Which type of gene mutation involves the removal of a base from a DNA sequence?

    • Base deletion
    • Base substitution
    • Base inversion
    • Base translocation

  3. During which process do spontaneous gene mutations most commonly occur in cells?

    • Protein translation
    • RNA transcription
    • Cellular respiration
    • DNA replication

  4. Which feature of the genetic code prevents some base substitutions from changing the amino acid sequence?

    • Non-overlapping code
    • Triplet code
    • Degenerate code
    • Universal code

  5. What is the term for an agent that increases the rate of gene mutation?

    • Mutagenic agent
    • Carcinogenic agent
    • Pathogenic agent
    • Teratogenic agent

  6. Which process during meiosis can lead to a change in whole chromosome number?

    • Non-disjunction
    • Independent assortment
    • Cytokinesis
    • Crossing over

  7. What type of gene mutation causes a frameshift downstream of the mutation site?

    • Inversion mutation
    • Translocation mutation
    • Base substitution
    • Base deletion

  8. Which term describes a cell or organism containing three copies of a specific chromosome?

    • Polyploidy
    • Monosomy
    • Trisomy
    • Diploid

  9. A cell has a diploid number of 2n = 46. What is the chromosome number of a gamete produced by a normal meiosis?

    • 11.5
    • 46
    • 23
    • 92

  10. Which term describes a mutation that has no effect on an organism's phenotype or survival?

    • Beneficial mutation
    • Neutral mutation
    • Silent mutation
    • Harmful mutation

  11. A base substitution altering one amino acid in an enzyme most directly affects which structure?

    • Phosphodiester backbone
    • Primary structure
    • Tertiary structure
    • Quaternary structure

  12. What effect does exposure to a mutagenic chemical have on bacteria?

    • Increases mutation rate
    • Stops transcription completely
    • Prevents all mutations
    • Decreases mutation rate

  13. A human somatic cell containing 47 chromosomes instead of 46 shows which type of mutation?

    • Gene mutation
    • Chromosome mutation
    • Frameshift mutation
    • Silent mutation

  14. Which process is the primary source of all new alleles within a population?

    • Gene mutation
    • Natural selection
    • Genetic drift
    • Chromosome non-disjunction

  15. Which type of mutation replaces one base with another without altering total sequence length?

    • Base insertion
    • Base duplication
    • Base deletion
    • Base substitution

  16. Why does deleting a single base usually have a major effect on the resulting protein?

    • Prevents DNA replication
    • Causes a frameshift
    • Degrades the mRNA
    • Stops transcription

  17. What specifically is altered by a gene mutation?

    • Total chromosome number
    • DNA base sequence
    • Centromere position
    • Histone protein structure

  18. Which type of mutation introduces a premature stop codon into a gene sequence?

    • Missense mutation
    • Silent mutation
    • Frameshift mutation
    • Nonsense mutation

  19. Ionising radiation increases the rate of gene mutation by acting as what?

    • A transcription factor
    • A restriction enzyme
    • A mutagenic agent
    • A hydrolytic enzyme

  20. A mutation in a gene changes a codon but the amino acid is unchanged. Which term best describes the code that allows this?

    • Haploid
    • Non-overlapping
    • Universal
    • Degenerate

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