National Certificate of Educational Achievement · Science

Genetics, Cell Biology, Gene Expression and Ecological Systems

35 practice questions, each with the answer and an explanation.

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Random questions from this topic, one at a time. You see the answer and the explanation straight after each one.

All 35 questions

  1. What is the basic repeating structural subunit (monomer) of a DNA molecule?
  2. According to Watson-Crick complementary base pairing rules, which nitrogenous bases pair together across the DNA double helix?
  3. What is the difference between a gene and an allele in genetics?
  4. What is the expected phenotypic ratio of offspring from a monohybrid cross between two heterozygous parents (Bb x Bb) where B is dominant?
  5. What is the sole source of completely new genetic alleles in a biological population?
  6. How does meiosis contribute to genetic variation among gametes (sperm and egg cells)?
  7. What is the difference in chromosome number between somatic (body) cells and gametes in humans and other diploid animals?
  8. Why are male mammals significantly more likely to inherit X-linked recessive genetic conditions (like red-green colour blindness) than females?
  9. What structural adaptation allows the kiwi (Apteryx) to forage effectively on the forest floor at night?
  10. What is the primary ecological threat posed by introduced Australian brushtail possums to native New Zealand forest ecosystems?
  11. In an ecological food chain, what role is performed by autotrophic primary producers?
  12. Why is only about 10% of energy transferred from one trophic level to the next higher level in a food pyramid?
  13. What is natural selection in evolutionary biology?
  14. What is an example of an endemic species in New Zealand?
  15. What cellular organelle is the site of aerobic cellular respiration in plant and animal cells?
  16. What is the function of enzymes in biochemical metabolic pathways?
  17. In a pedigree chart tracking an autosomal recessive trait, two unaffected parents have an affected daughter. How is this genetically explained?
  18. Explain why a somatic mutation (e.g., in a skin cell caused by UV sunlight) cannot be inherited by future offspring, whereas a gametic mutation can.
  19. In a population of endangered kākāpō on Whenua Hou island, why does a severe genetic bottleneck increase extinction vulnerability?
  20. Two genes in a fruit fly are located very close together on the same chromosome. What phenotypic outcome is observed in dihybrid test crosses, and why?
  21. In a New Zealand native beech forest ecosystem, a mast seeding year produces an immense abundance of beech seeds. What cascading ecological consequence typically unfolds over the following two years?
  22. Why does non-disjunction during meiosis I result in all four gametes carrying abnormal chromosome numbers, whereas non-disjunction in meiosis II affects only two gametes?
  23. How does the structure of a chloroplast's thylakoid membrane system relate to its function during the light-dependent reactions of photosynthesis?
  24. What is the function of mRNA (messenger RNA) in protein synthesis?
  25. What process produces identical diploid daughter cells for growth and tissue repair in multicellular organisms?
  26. Which of the following is an abiotic factor influencing a tidal rock pool ecosystem along the Wellington coast?
  27. What is the term for a symbiotic relationship in which both species benefit from the interaction?
  28. What is a codon in molecular genetics?
  29. Why is biodiversity critical for ecosystem resilience in the face of climate change and environmental disturbance?
  30. What happens during the light-independent reactions (Calvin cycle) of photosynthesis?
  31. In a pedigree analysis, what does a horizontal line connecting a circle and a square represent?
  32. What is osmosis, and in what direction do water molecules move across a selectively permeable cell membrane?
  33. How do plant root hair cells absorb dissolved mineral nitrate ions from low concentrations in soil water into high concentrations inside the cell?
  34. What information does a human karyotype analysis provide to medical geneticists?
  35. On Rangitoto Island in the Hauraki Gulf, how did primary ecological succession proceed on bare basaltic volcanic lava?

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