Biology 2.4

• What is definition of variation

  Diffences between individuals of a specie
• Two types of variations

  Continuous and discontinuous
• What is continuous variation

  Differences in heights, weights between people
• How is continuous shown on a growth

  A hump can be drawn though small to big then back to small
• What is discontinuous variation 


  The differences between hair colour, eye colour between people and skin colour
• How is discontinuous variation show on a graph

  Random sizes
• sexual reprodcaution 


  Uses meiosis sex between two parents and results in different offspring’s
• What is asexual reproduction

  Used mitosis offsprings are identical to the parent (clones) 1 parent
• What are clones 


  An organism that is genetically identical to the parent
• What is a mutation

  The change in a gene or DNA cause by ionising radiation
• Mutation makes a new base triplet, these means a different amino acid is coded for
• How is a mutation caused 


  If one base is changed a new amino acid might be coded for which might change the structure of a protein
• muattion rates can be increased by ionising radiation such as UV rays from the sun and sunbeds or a high expose rate to X rays or gamma rays
• What is cystic fibrosis

  An inherited recessive genetic condition cause by a mutation in a specific gene
• Cystic fibrosis must have 2 copies of the mutated gene to have the disease e.g nn as a genotype
• What does cystic fibrosis cause

  Thick, sticky mucus to block the bronchioles of the lungs
• What is the genotype of individuala with cystic fibros

  Homozygous recessive

  ff
• What is the genotype of carries of cystic fibrosis

  Heterozygous Ff
• What is a gene therapy 


  A number of techniques used to counteract the effects of a defective allele within DNA
• What is used to treat cystic fib

  An inhaler
• What is the function of a inhaler 


  Used to she don’t al versions of the gene to the lung tissue so that they can make the protein needed to prevent the symptoms of cystic fibrosis
• What is the main problem with a inhaler

  The cells which revive the normal version of the gene will die and be replaced by cells with the fauly gene
• an inhaler treatment will have to be repeated
• what happens if the triplet code is broken/changed

  Mutation
• What is natural selection


  Finish
• How does a mutation affect Dna

  Changes the shape of a gene codes for a different amino acid which coded for a different protein and changed the triplet code