Reproduction

• Asexual reproduction 


  One parent

  Offspring genetically identical to parent

  ADV: Population can increase rapidly

  DIS: Lack of diversity, Slow evolution
• Sexual reproduction

  Two parents

  Offspring genetically different

  to each other and parents

  ADV: Variation so disease less likely

  DIS: Inefficiente
• DNA

  Has a double helix structure
• Base pairs 


  A + T , C + G
• Nucleotide 


  Made up of a base a sugar and a phosphate
• Chromosome 


  Long threads of DNA
• Gene 


  Code for a protein
• Meiosis 


  All chromosomes copied and replicated

  Cell divides twice

  4 Gametes form

  Chromosomes now single (Haploid) meaning gametes are genetically different

  4 haploid daughter cells are formed
• Mitosis 


  DNA replicates forming two copies of each chromosome

  Nuclear membrane breaks down

  Chromosomes line up in the centre of the cell

  Pulled to each end and nucleus divides

  Cytoplasm and cell membrane divide

  2 Genetically identical daughter cells are formed