Topic 6 – Inheritance, Variation and Evolution

• Cell hierarchy


  • Cell
  • Nucleus
  • Chromosome
  • DNA
  • Gene
• Levels of biological organisation

  • Cell
  • Nucleus
  • Chromosome
  • DNA
  • Gene
• Gene


  A section of the DNA that produces a protein - controls characteristics
• Gene


  A section of the DNA that produces a protein - controls characteristics
• Gene to Characteristic


  1. Gene

  2. mRNA

  3. Sequence of amino acids

  4. Protein

  5. Characteristic
• Gene to Characteristic


  1. Gene

  2. mRNA

  3. Sequence of amino acids

  4. Protein

  5. Characteristic
• GENOME


  The entire set of genetic material in an organism
• GENOME


  The entire set of genetic material in an organism
• Uses of genome


  • Link genes to diseases
  • Develop effective treatments
  • Investigate relationships / migration patterns
• Uses of genome


  • Link genes to diseases
  • Develop effective treatments
  • Investigate relationships / migration patterns
• DNA


  A POLYMER (many nucleotides joined)
• DNA


  A POLYMER (many nucleotides joined)
• Components of a nucleotide

  • Sugar
  • Phosphate (backbone)
  • Base
• Components of a nucleotide

  • Sugar
  • Phosphate (backbone)
  • Base
• DNA structure


  • Double helix
  • Complementary bases (A + T) & (C + G)
  • Order of bases = order of amino acids
  • Three bases (CODON) = 1 amino acid
  • Non-coding region (no amino acids)
  • Non-coding region (control expression of gene, ON/OFF)
• DNA structure


  • Double helix
  • Complementary bases (A + T) & (C + G)
  • Order of bases = order of amino acids
  • Three bases (CODON) = 1 amino acid
  • Non-coding region (no amino acids)
  • Non-coding region (control expression of gene, ON/OFF)
• mRNA


  Carries DNA code from nucleus to ribosome
• mRNA


  Carries DNA code from nucleus to ribosome
• Types of Proteins


  • Enzymes
  • Structural
  • Hormones
  • Biological Catalysts
• Types of Proteins


  • Enzymes
  • Structural
  • Hormones
  • Biological Catalysts
• Collagen


  Strong, found in skin and hair
• Proteins


  • Collagen - strong
  • Skin and hair
  • Chemical Messengers
• Hormones


  Chemical Messengers
• Types of Mutations


  • Insertion / Deletion - have knock on effects (affect more than 1 A.Acid)
  • Substitution - no knock-on affect
• Types of Mutations


  • Insertion / Deletion (have knock on effects)
  • Substitution (no knock-on affect)
• Effect of mutation in coding region

  1. Gene

  2. mRNA

  3. amino acids

  4. shape of protein

  5. function of protein
• Effect of mutation in coding region

  1. Gene

  2. mRNA

  3. amino acids

  4. shape of protein

  5. function of protein
• Change in the shape (active site) of an enzyme - it might not function properly
• Change in shape (active site) - enzyme might not function properly
• Mutation in the NON-CODING region affects expression (ON/OFF)
• Reproduction types


  • Sexual
  • Asexual
• Types of Reproduction


  • SEXUAL
  • ASEXUAL
• Sexual reproduction


  • Two parents
  • Fusion of male and female gametes (fertilisation)
  • Mixture of both parents
• Sexual Reproduction


  • TWO parents
  • Fusion of male and female gametes (fertilisation)
  • Mixture of both parents
• Asexual reproduction


  • One parent
  • No fusion of gametes
  • Genetically identical Offspring
  • Clones
• Asexual Reproduction


  • ONE parent
  • No fusion of gametes
  • Genetically identical Offspring
  • Clones
• Advantages of sexual reproduction

  • Offspring variation = ^ survival chance
  • Genes passed down – natural selection
  • Artificial Selection (humans choose)
• Advantages of Asexual Reproduction


  • Only one parent needed
  • Less energy (no finding mate)
  • Faster
  • Produce many clones
• Advantages of asexual reproduction

  • Only one parent needed
  • Less energy (no finding mate)
  • Faster
  • Produce many clones
• Advantages of Sexual Reproduction

  • Offspring variation = ^ survival chance
  • Genes passed down - natural selection
  • Artificial Selection (humans choose) - More food production (more meat)