2.5 – DNA, genetics and evolution

Pages 61 – 71 of the CGP revision notes.

Key questions

  • What do genes do?
  • What is a DNA fingerprint and how is it used?
  • What is mitosis? Where what is it used for?
  • What is meiosis? How does it work?
  • What are stem cells? How may they be used? Why do some people oppose this?
  • How is the sex of a baby determined?
  • What do these terms mean: gene, allele, dominant, recessive, homozygous, heterozygous,genotype, phenotype.
  • Draw a genetic diagram to show the result of a cross between two heterozygous parents.
  • How does the inheritance of cystic fibrosis differ from that of polydactyly?
  • What are the pros / cons of genetic screening?
  • How can family trees be used to show inheritance of a gene through generations?
  • Three ways in which fossils form?
  • Why doesn’t  the fossil record tell us everything about evolution?
  • What are the causes of extinction?
  • Explain speciation (using “isolation” and “natural selection”)?