UnderstandBand 3
1. Which of the following correctly orders genetic structures from smallest to largest?
AChromosome → Gene → DNA → Nucleotide
BNucleotide → Gene → DNA → Chromosome
CDNA → Chromosome → Gene → Nucleotide
DGene → Nucleotide → Chromosome → DNA
UnderstandBand 3
2. What is the complementary strand for the DNA sequence ATGCGT?
AATGCGT
BUACGCA
CTACGCA
DTAGCGT
UnderstandBand 3
3. Which term describes a version of a gene?
AAllele
BChromosome
CNucleotide
DProtein
ApplyBand 4
4. Two heterozygous parents (Bb) have a child. What is the probability the child will be homozygous recessive (bb)?
A0%
B25%
C50%
D25% — wait, let me recalculate: Bb x Bb gives BB, Bb, Bb, bb = 25% bb
UnderstandBand 3
5. Which of the following is a transgenic organism?
AA purebred German shepherd dog
BA bacterium that produces human insulin
CA wild kangaroo in the outback
DA plant grown from heirloom seeds
UnderstandBand 4
6. What is the primary ethical concern with using CRISPR to edit human embryos?
ACRISPR is too expensive for most families
BScientists do not know how to use CRISPR yet
CChanges to embryo DNA would be inherited by all future generations
DCRISPR only works on plant DNA
UnderstandBand 3
7. What is natural selection?
AThe process by which individuals with advantageous traits survive and reproduce more successfully
BHumans choosing which animals to breed together
COrganisms deliberately changing their DNA to suit the environment
DThe random extinction of all species over time
UnderstandBand 3
8. Which of the following is NOT a line of evidence for evolution?
AFossil record showing gradual change in species over time
BHomologous structures in different species
CDNA sequence similarities between related species
DThe fact that all organisms look exactly the same
UnderstandBand 4
9. What is the main difference between homologous and analogous structures?
AHomologous structures look different but have different functions; analogous structures look similar but have the same function
BHomologous structures have similar underlying anatomy but different functions (common ancestry); analogous structures have similar functions but different anatomy (convergent evolution)
CThere is no difference — they are the same thing
DHomologous structures are only found in fossils, while analogous structures are only found in living organisms
ApplyBand 4
10. Overuse of antibiotics in agriculture has led to an increase in antibiotic-resistant bacteria. This is an example of:
AArtificial selection by farmers
BGenetic modification of bacteria
CNatural selection favouring resistant bacteria
DBacteria learning to avoid antibiotics
UnderstandBand 3
11. What is speciation?
AThe formation of a new species from an existing population
BThe extinction of an entire species
CThe process of selective breeding
DThe mutation of a single gene
UnderstandBand 4
12. Geographical isolation can lead to speciation because:
AIt forces all individuals to mutate at the same rate
BIt prevents any reproduction from occurring
CIt makes all populations genetically identical
DSeparated populations experience different selection pressures and accumulate genetic differences over time
UnderstandBand 3
13. Which statement about human evolution is correct?
AHumans evolved from modern chimpanzees
BHumans and modern apes share a common ancestor
CHuman evolution has stopped completely
DOnly humans have DNA; other primates do not
AnalyseBand 4
14. A scientist finds that two species have very similar DNA sequences but very different physical appearances. What does this suggest?
AThe species are not related at all
BDNA evidence is always wrong
CThe species share a recent common ancestor but have been shaped by different environmental pressures
DPhysical appearance is the only reliable indicator of relatedness
AnalyseBand 5
15. Which statement best explains why genetic variation is essential for both natural selection and the success of selective breeding?
ABoth processes require differences in traits to act upon — without variation, there is nothing to select
BVariation only matters in nature; selective breeding works without any variation
CNatural selection creates variation, while selective breeding destroys it
DVariation is harmful and should be eliminated in both contexts
UnderstandBand 3
16. Explain the relationship between DNA, genes, chromosomes and alleles. Include a diagram description in your answer. 4 MARKS
ApplyBand 4
17. Compare selective breeding and genetic modification as methods of changing organisms. Include one advantage and one limitation of each. 4 MARKS
Write a comparison in your book.
ApplyBand 4
18. Explain how antibiotic resistance in bacteria demonstrates evolution by natural selection. Use the terms variation, selection pressure, survival and inheritance in your answer. 4 MARKS
Use all four terms in your book.
AnalyseBand 5
19. Evaluate the claim: "Genetic technologies are always beneficial to society." In your answer, provide at least one supporting argument and one counter-argument, using specific examples. 4 MARKS
Write a balanced evaluation in your book.
AnalyseBand 5
20. Synthesise your understanding of the entire unit by explaining how DNA, genetic variation, natural selection and evidence are all connected in the theory of evolution. 4 MARKS
Write a synthesis in your book.