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• The first step is to identify the problem or issue that needs to be addressed.
• EnergyInternal energy
• Unicellular organism


  A single-celled organism
• Types of organisms


  • Prokaryotes
  • Protists
  • Fungi
  • Plants
  • Animals
• Characteristics of organisms


  • Unicellular or Multicellular
  • Cytoplasm?
  • Cell Membrane?
  • Nucleus?
  • Mitochondria?
  • Cell Wall?
  • Chloroplasts?
• Viruses are not considered living organisms
• Order of size


  1. yeast

  2. human

  3. cold virus

  4. multicellular fungus
• Diffusion


  The process by which substances are taken in by unicellular organisms
• Aerobic respiration of yeast

  Glucose + Oxygen → Carbon dioxide + Water
• Respiration of yeast


  Causes the dough to rise
• Conditions yeast needs to grow

  • Warm temperature
  • Moist environment
  • Food source (sugar)
• Anaerobic respiration


  The respiration of microorganisms without oxygen
• Anaerobic respiration


  Glucose → Ethanol + Carbon dioxide
• Components of a bacterial cell

  • Cell wall
  • Cell membrane
  • Cytoplasm
  • Nucleus
  • Ribosomes
  • Plasmids
  • Flagella
• Uses of lactic acid produced by anaerobic respiration of bacteria

  • Cheese production
  • Yogurt production
• Flagella


  Allows bacteria to move
• Food chain


  Algae → Mussels → Octopus → Shark
• Hydrocarbon


  A compound made only of carbon and hydrogen
• Hydrocarbon combustion


  Hydrocarbon + oxygen → water + carbon dioxide
• Combustion


  An oxidation reaction where substances react with oxygen
• Metal oxidation


  Metal + oxygen → metal oxide
• In a reaction, the mass of the reactants is always the same as the mass of the products
• Metals heated in air


  Appear to gain mass
• The difference in mass is the mass of oxygen that reacted
• Hydrocarbon fuel combusts


  Appears to lose mass because the products (carbon dioxide, water vapour) are lost into the air
• Phlogiston


  A substance that was thought to be released during combustion before oxygen was discovered
• The phlogiston theory could not explain why metals gained mass when they reacted with air
• Fire triangle


  • The three factors needed for a fire to burn: fuel, oxygen, heat
  • If any factor is removed, the fire will go out

  
• Fire extinguishers


  • Water extinguishers remove heat
  • Powder and carbon dioxide extinguishers exclude oxygen
  • Foam extinguishers can both remove heat and exclude oxygen
• Oil fires should not be treated with water because the water sinks through the oil, which heats up and causes the water to evaporate, which can spread the fire
• Hazard symbols


  Explain why a substance must be handled carefully
• Complete combustion


  Fuel reacts completely with oxygen to form carbon dioxide and water
• Incomplete combustion


  Fuel only partly reacts with oxygen to form carbon dioxide, water, carbon monoxide and carbon (soot)
• Sulfur combustion


  Sulfur + oxygen → sulfur dioxide
• Nitrogen combustion


  Nitrogen + oxygen → nitrogen oxides
• Many products from burning fossil fuels are pollutants that harm habitats and organisms
• Acid rain

  Rain water made more acidic by dissolved sulfur dioxide and nitrogen oxides
• Sulfur dioxide and nitrogen oxides can be removed from power station chimneys by neutralisation, and by using catalytic converters on vehicle exhausts</b>
• Catalytic converters also remove carbon monoxide, another pollutant
• Greenhouse effect

  Greenhouse gases in the Earth's atmosphere keep the Earth's surface warm