Cambridge A-Level · Biology

Genetics, Evolution and Biotechnology

19 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 19 questions

  1. What term describes the different forms of a gene found at the same locus on a chromosome?
  2. Two heterozygous parents (Bb) have children. B is dominant over b. What is the probability that a child shows the recessive phenotype?
  3. In a test cross, an organism showing the dominant phenotype is crossed with a homozygous recessive. What does a 1:1 ratio of offspring show?
  4. A cross of two dihybrid heterozygotes (AaBb x AaBb) with independent assortment gives which phenotype ratio?
  5. Cystic fibrosis is caused by a recessive allele. Two unaffected parents have an affected child. What are the genotypes of the parents?
  6. What is meant by codominance?
  7. In a population in Hardy-Weinberg equilibrium, the frequency of the recessive allele q is 0.2. What is the frequency of heterozygotes?
  8. Which process in meiosis produces new combinations of alleles on a chromosome?
  9. What is natural selection?
  10. Bacteria in a hospital become resistant to an antibiotic. Which statement best explains this?
  11. A bird species has two beak sizes. A drought leaves only large, hard seeds. Which type of selection is this likely to cause?
  12. What is allopatric speciation?
  13. Which technique is used to make many copies of a small sample of DNA?
  14. What does gel electrophoresis separate?
  15. What is the role of restriction enzymes in genetic engineering?
  16. A student wants to know if a gene has been taken up by bacteria on a plasmid carrying ampicillin resistance. What should the student do?
  17. Which statement about the Hardy-Weinberg principle is correct?
  18. What is genetic drift?
  19. The bottleneck effect reduces a population to a few individuals. What is the likely effect on the population?

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