Leaving Cert Ireland · Biology

Cells, Genetics, Ecology and Human Biology

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

Practise Cells, Genetics, Ecology and Human Biology now

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

All 36 questions

  1. Which organelle is the main site of aerobic respiration in an animal cell?
  2. What is an enzyme?
  3. How many cells result from one complete round of mitosis in a diploid cell?
  4. What is osmosis?
  5. Which tissue carries water and minerals upwards from the roots to the leaves of a plant?
  6. Which blood cells carry oxygen from the lungs to the tissues?
  7. How many chromosomes are in a normal human body (somatic) cell?
  8. Where do the light-dependent reactions of photosynthesis take place?
  9. About 28% of the bases in a double-stranded DNA molecule are thymine. What percentage are cytosine?
  10. What is produced when yeast respires anaerobically?
  11. Two heterozygous tall pea plants (Tt) are crossed. What is the expected phenotype ratio of the offspring?
  12. Why does a pyramid of energy always have an upright shape?
  13. Which sequence correctly shows the main steps of the nitrogen cycle in the soil?
  14. Why is the wall of the left ventricle thicker than that of the right ventricle?
  15. In which part of the nephron does ultrafiltration take place?
  16. Which organ produces insulin, and what is its effect?
  17. What term describes the way in which a rise in a factor triggers a response that reverses the rise?
  18. Which cells produce antibodies?
  19. Why does a vaccination give long-term protection?
  20. What is the role of restriction enzymes in genetic engineering?
  21. Where does translation take place in a cell?
  22. Which statement describes natural selection?
  23. What causes eutrophication of a lake?
  24. Why does a shoot grow towards a light source?
  25. What is the general word equation for aerobic respiration?
  26. Which of the following is an abiotic factor in an ecosystem?
  27. What is transpiration?
  28. A student investigates the effect of pH on the activity of an enzyme. Which control would best show that it is the enzyme causing the reaction?
  29. How many genetically different gametes can an individual of genotype AaBb produce, if the genes are on different chromosomes?
  30. Two unaffected parents have a child with a genetic condition. What can be concluded?
  31. An enzyme-controlled reaction speeds up as substrate concentration rises, but levels off at high concentration. What explains the levelling off?
  32. A tall plant (Tt) is crossed with a dwarf plant (tt). Out of 64 offspring, how many tall plants are expected?
  33. In a mark-recapture study, 40 snails are marked and released. A later sample of 30 snails contains 5 marked ones. Estimate the population size.
  34. A field of 500 square metres is sampled with twelve 1 m quadrats, and the mean count is 4 daisies per quadrat. Estimate the number of daisies in the field.
  35. Which process produces four genetically different haploid cells from one diploid cell?
  36. Which statement about phloem is correct?

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