Biological approach

• Neurochemical

  The chemical processes occuring in the nervous system. For example, the actions of neurotransmitters within the brain
• What is a gene


  They are biochemical units of heredity that make up chromosomes. They are segments of DNA molecules that code physical features. For example eye colour and psychological features
• Concordance rates


  The extent to which both twins share the same characteristic
• Genotypes


  A person's unique genetic make - up that is coded in their chromosomes and fixed at conception.
• Phenotype


  The expression of a genotype is influenced by environmental factors and becomes a person's phenotype
• Evolution


  Gradual changes in an inherited characteristic of a species over many generations
• Natural selection


  The way that any genetically determined bevaiour that enhances the ability to survive and reproduce will continue in future generations
• A01 - Humans are biological organisms made up of physicological processes