Enzymes

• Enzymes


  Biological catalysts that help speed up processes of breaking down, building up, and changing a substrate
• Substrate


  Reactant
• Enzymes


  • Long protein molecules
  • Folded to form a specific shape
  • Active site fits a specific substrate molecule
• Lock and key mechanism

  The substrate fits into the active site of an enzyme
• Enzyme action


  1. Substrate binds

  2. Enzyme and substrate collide

  3. Reaction occurs

  4. Products released
• Enzymes don't change a reaction in any way, they just make it happen faster
• Temperature effect on enzymes

  Increases enzyme activity until about 50°C, then protein chain unravels
• Denatured


  When the active site of the enzyme changes due to temperature or pH
• Above or below the optimum pH


  The enzyme gets denatured
• Osmosis is the movement of water molecules across a partially permeable membrane from an area of high water concentration to a low water concentration
• Diffusion


  Spreading of particles from a high concentration to a low concentration
• High water concentration means lots of water molecules
• Animal cells do not have a cell wall unlike plant cells
• In pure water (dilute solutions) animal cells burst
• In syrup (concentrated solutions) animal cells shrink
• Plant cells have cell walls which stop them from bursting from water from osmosis
• In pure water (a dilute solution) plant cell contents become turgid
• In a solution like syrup (a high concentration solution) the plant cell turns flaccid and shrinks
• Photosynthesis


  The process where plants transform light energy into chemical energy
• Photosynthesis equation


  • 6CO₂
  • 6H₂O
  • CH₁₂O₆
  • 6O₂
• Chlorophyll


  The pigment that gives plants their green colour and helps in photosynthesis by absorbing light
• Chloroplasts


  The plant cell structure where photosynthesis occurs
• Xylem


  The plant vascular tissue that moves water and dissolved minerals upwards and provides physical support
• Photosynthesis is an endothermic reaction
• To perform photosynthesis you must have a source of light, water, and CO₂
• Organisms other than plants that can go through photosynthesis include algae and the emerald green sea slug