Decomposition

• What happens to the carbon in dead animals and plants?

  It is broken down by decomposing microorganisms
• What role do decomposers play in the carbon cycle?

  They recycle matter and return carbon to the atmosphere
• What are examples of decomposing microorganisms?

  Bacteria and fungi
• What can happen to carbon in dead remains under certain conditions?

  It can be converted to fossil fuels
• What has been happening to fossil fuels over the last 200 years?

  Humans have been burning large amounts of them
• What is the effect of burning fossil fuels on the atmosphere?

  It releases a large amount of carbon dioxide
• What role do decomposing microorganisms play in the carbon cycle?

  They decompose waste materials and dead remains, returning carbon to the atmosphere
• What do decomposers return to the soil?

  Mineral ions
• What is a compost heap and its purpose?

  • A compost heap is a pile of dead plant material.
  • It is used to decompose the material into compost.
  • Compost is rich in minerals needed for plant growth.
• What are the optimal conditions for decomposition?

  Warm temperature, adequate moisture, and sufficient oxygen
• How does temperature affect decomposition?

  Decomposition occurs faster at warmer temperatures due to enzyme activity
• What happens to enzymes at high temperatures during decomposition?

  They can denature, causing decomposers to die
• Why is moisture important for decomposition?

  Many chemical reactions in decay require water
• What conditions make a good compost heap?

  Moist conditions
• What is the role of oxygen in decomposition?

  Decomposers require oxygen for aerobic respiration
• What is the effect of mixing compost with a gardening fork?

  It allows more oxygen to enter and increases surface area for decomposers
• What occurs during anaerobic decay?

  Decomposing microorganisms produce a mixture of gases, including methane
• What is biogas and how is it produced?

  Biogas is produced during anaerobic decay and includes gases like methane
• What materials are often used in small-scale biogas generators?

  Plant materials such as food waste or animal manure
• What do decomposers produce under anaerobic conditions?

  Biogas
• Why does milk sour when left at room temperature?

  Bacteria in the milk use enzymes to produce acidic molecules
• What enzyme is used to model decay in the practical?

  Lipase
• What is the process of modeling decay in this experiment?

  • Use lipase to break down fat molecules in milk
  • Measure the time taken for the milk solution to turn yellow
  • Observe the change in pH as fatty acids are released
• What is the initial color of the solution when sodium carbonate is added to the milk?

  Purple
• What does the color change from purple to yellow indicate in the experiment?


  It indicates that the milk solution has become acidic
• What is the dependent variable in this experiment?

  The time taken for the milk solution to turn yellow
• What are the control variables in this experiment?

  The volumes of lipase, milk, sodium carbonate solution,
• Why is it important to use a clean test tube for each experiment?

  To prevent traces of lipase from triggering the reaction prematurely
• What is the expected trend in the reaction rate at different temperatures?

  • Reaction is slow at low temperatures
  • Fastest rate at optimum temperature
  • Reaction slows down and may stop at high temperatures due to enzyme denaturation
• What happens to enzymes at temperatures higher than the optimum?

  They denature and the reaction may stop completely
• How do decomposing microorganisms behave in warm conditions?

  They work faster, but not in hot conditions due to enzyme denaturation