molecules of life

• food

  source of all materials required by an organism to:

  -provide energy for life processes

  -provide raw materials for building an repair

  -conrol matabolism
• bio molecules

  chemicals made by an organism
• anabolic reactions


  covert smaller molecules into larger ones
• catabolic reactions


  Complex molecules are broken down to simpler ones and energy is released.
• all living things need food
• functions of food:

  • provide energy for life processes
  • provide raw materials for building and repair
  • control metabolism
• biomolecules are chemicals made by an organism
• living things are made of:

  • carbon (C)
  • hydrogen (H)
  • oxygen (O)
  • nitrogen (N)
  • sulfur (S)
  • phosphorus (P)
• there are four main types of biomolecules in food :

  • carbohydrates
  • lipids
  • proteins
  • vitamins
• carbohydrates are composed of C, H and O
• carbohydrate formula Cx(H2O)y , where x often equals y
• the ratio of H:O in carbohydrates is 2:1
• the molecular subunit of carbohydrates is sugar
• glucose

  C6H12O6
• there are three types of carbohydrates in living things:

  • monosaccharides
  • disaccharides
  • polysaccharides
• monosaccharides are composed of one sugar unit.

  examples: glucose, fructose

  food sources: fruit, honey
• disaccharides are composed of two sugar units.

  examples: sucrose (table sugar), maltose, lactose

  food sources: sweets, milk
• polysaccharides are composed of many sugar units.

  examples: starch, cellulose (fibre), glycogen

  food sources: potatoes, rice, bread