NSW HSC · HSC Biology

Heredity and Genetic Change

41 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 41 questions

  1. What is the outcome of meiosis in a diploid cell that has completed both divisions?
  2. Crossing over during prophase I of meiosis increases genetic variation because it:
  3. Independent assortment in meiosis leads to genetic variation because:
  4. Two heterozygous tall pea plants (Tt) are crossed, with tall (T) dominant over short (t). What is the expected ratio of tall to short offspring?
  5. A tall pea plant of unknown genotype is crossed with a short plant. The 26 offspring are 12 tall and 14 short. What is the best conclusion?
  6. Two unaffected parents have a child with an autosomal recessive condition. Which statement is correct?
  7. A woman who is a carrier for red-green colour blindness (X-linked recessive, XCXc) and a man with normal vision (XCY) have a child. What is the probability that the child is colour blind?
  8. A man with blood group A (IAi) and a woman with blood group B (IBi) have a child. What is the probability that the child has blood group O?
  9. Where in a eukaryotic cell are polypeptides assembled during translation?
  10. What is meant by an epigenetic change?
  11. In sickle cell disease, a single base substitution in the gene for haemoglobin changes one amino acid. This is an example of:
  12. A population of 100 diploid individuals has 36 AA, 48 Aa and 16 aa. What is the frequency of the allele A?
  13. Which set of conditions is required for natural selection to change a population?
  14. What is a main genetic risk of long-term selective breeding of a small group of animals?
  15. Bt cotton has been developed using a gene from the bacterium Bacillus thuringiensis. What type of organism is cotton, as a result?
  16. Which ethical concern is specific to editing the genes of a human embryo, compared with treating the cells of an adult patient?
  17. A small group of birds colonises an island, and the group has a higher frequency of one allele than the original population. This is an example of:
  18. Bacteria are exposed to an antibiotic. A few survive and multiply, and later the whole population is resistant. This is best explained by:
  19. Two lineages from a common ancestor each accumulate one base change per million years. Their DNA sequences differ at 12 bases. Approximately when did the lineages diverge?
  20. Mendel's law of segregation states that:
  21. Which molecule carries the genetic code from the nucleus to the ribosome?
  22. During which stage of the cell cycle is DNA replicated?
  23. Which process produces gametes with half the chromosome number of the parent cell?
  24. In meiosis, which event during prophase I increases genetic variation?
  25. A heterozygous tall pea plant (Tt) is crossed with a short plant (tt). What proportion of offspring are expected to be short?
  26. Two carriers of cystic fibrosis, an autosomal recessive condition, have a child. What is the probability that the child has the disorder?
  27. A man with a sex-linked recessive condition has children with a woman who is not a carrier. What proportion of their daughters will be carriers?
  28. Which technique separates DNA fragments according to their size?
  29. What is the main purpose of the polymerase chain reaction (PCR)?
  30. Which enzymes cut DNA at specific recognition sequences?
  31. Which enzyme joins DNA fragments together in recombinant DNA technology?
  32. A point mutation changes one codon from GAA to GAG, and the amino acid remains glutamic acid. What type of mutation is this?
  33. A deletion of one base from a gene most likely results in which type of mutation?
  34. Which of the following is a source of new alleles in a population?
  35. What is natural selection?
  36. A small population is reduced by a storm so that only a few individuals remain, and rare alleles are lost. This is an example of:
  37. A few individuals colonise a new island and their allele frequencies differ from the original population. This is known as:
  38. Which of these is evidence for evolution from comparative anatomy?
  39. Which of the following is an example of artificial selection?
  40. Which of the following best describes a transgenic organism?
  41. What does the term 'genotype' refer to?

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