B14d Decomposition (triple only) Flashcards
What does decomposition mean?
Breakdown of dead materials into simpler organic matter
How do decomposers breakdown dead material?
Decomposers release enzymes which catalyse the breakdown of dead material into smaller molecules
Name factors that affect the rate of decomposition
Temperature
Water
Availability of oxygen
Why is oxygen requited for decomposition?
Requited by most decomposers for aerobic respiration
How does the availability of oxygen affect the rate of decomposition?
As oxygen levels increase the rate of decomposition increases
Why can decomposition still occur in the absence of oxygen?
Some decomposers respire anaerobically
Describe how soil water content affects the rate of decomposition?
Decomposers require water to survive
In moist conditions the rate of decomposition is high
In waterlogged soils there is little oxygen for respiration so the rate of decomposition decreases
Describe how temperature affects the rate of decomposition?
Decomposers release enzymes
Rate highest at 50C (optimum)
Lower temperature enzymes work slowly therefore rate decreases
Higher temperature enzymes denature and decomposition stops
How is the rate of decomposition calculated?
Rate of change = change in value/time
Describe the conditions needed for rapid decay of waste biological material
Warm temperature - optimum temperature for enzymes
Oxygen - for aerobic respiration
Water - required for metabolism
What is compost?
Nutrient rich product produced by rapid decomposition of dead plants and animal waste in optimum conditions.
Used by gardeners and farmers
Why is compost used?
Natural fertiliser
Contains lots of minerals
Promotes growth of crops or garden plants
Describe how biogas generators work
Produce methane
Due to anaerobic decomposition of animal waste
Methane is used as a fuel
What happens to the pH when fresh milk is decomposed?
Decreases
What causes the decrease in pH when milk decomposes?
Proteins broken down into amino acids
Lipids broken down into fatty acids
Fatty acids and amino acids decrease the pH