Decomposition

• what happens when organisms die or release waste

  decomposition
• define the term 'decomposition'

  • breakdown of organic matter into atmosphere or soil
• which 3 factors affect the rate of decomposition

  • temperature
  • water content
  • oxygen availability
• how does most decomposition take place

  • by decomposers like microorganisms
• describe how temperature affects the rate of decomposition

  • increasing temperature = increases rate of enzyme controlled reaction
  • so increases rate of decomposition
  • if temperature too high -> enzyme will denature + can't take place
• describe how water availability affects rate of decomposition

  • takes place faster in MOIST conditions
  • needs water to survive
  • to carry out biological processes
• describe how oxygen availability affects the rate of decomposition

  • takes place faster if plenty of oxygen available
  • needs aerobic respiration to work
• how do we preserve food

  by slowing down the rate of decomposition
• what are the 3 ways to slow down the rate of decomposition

  • reducing temperature
  • reducing water content
  • reducing oxygen availability
• how does reducing the temperature slow down the rate of decomposition

  • storing food in fridge or freezer
  • lowers temp -> slows down rate of decomposition
  • freezers completely stop the rate
• how does reducing the water content slow down the rate of decomposition

  • drying water removes the water
  • decomposers needs water to survive + reproduce
  • adding salt or sugar causes decomposers to lose water by osmosis
• how does reducing oxygen availability slow down the rate of decomposition

  • storing food in airtight to stop decomposers from getting to food
  • sealed food can be sterilised -> by exposing it to high pressure + temperature to kill any microorganisms present
• how can you sterilise food

  • exposing it to high pressure + temperatures
  • kills any microorganisms present
• what is compost

  • decomposed organic matter
  • used as fertiliser for crops + garden plants
• how can the production of compost be sped up

  • quickest in warm + moist + oxygen rich conditions
• what creates the best environment for decomposers

  compost bins
• how are some compost bins created to maximise decomposition

  • mesh sides to increase O2 availability
  • moisture + heat maintained by generation of O2 + thermal energy
  • some insulated to raise temp