Decay Flashcards
1
Q
Compost
A
- decomposed organic matter used as a natural fertiliser
2
Q
process of decomposition
A
- microorganisms like bacteria, fungi, detritus feeders cause decay by feeding on dead matter
3
Q
Factors affecting rate of decay
A
- temperature
- oxygen availability
- water availability
- number of decay organisms
4
Q
Temperature on rate of decay
A
- warmer temperatures increase rate of decay
- increased rate of enzyme action
- too hot, rate slows down/stops as enzymes are destroyed and organisms die
- cold temperatures slow down rate
5
Q
Oxygen availability on rate of decay
A
- oxygen needed to respire and survive
- except for microorganisms that anaerobically respire
6
Q
Water availability on rate of decay
A
- rate increases in moist environments
- water needed by organisms to carry out biological processes
7
Q
Number of decay organisms on rate of decay
A
- more microorganisms/detritus feeders increases rate
8
Q
Biogas
A
- consists of methane which is burned as fuel
9
Q
How is biogas made?
A
- microorganisms decay plant and animal waste anaerobically
- produces methane gas
10
Q
Producing biogas on a larger scale
A
- made in simple fermenters
- digester/generator
- kept at constant temperature to keep microorganisms respiring
11
Q
Storage of biogas
A
- cant be stored as liquid
- used instantly
12
Q
Uses of biogas
A
- heating
- cooking
- lighting
- powering turbines to generate electricity
13
Q
Batch biogas generators
A
- makes biogas in small batches
- manually loaded with waste
- left to digest
- products cleared away at end of each session
14
Q
Continuous biogas generators
A
- waste continuously fed in
- produced at steady rate
- suited to large-scale projects
15
Q
How to investigate effect of temperature on rate of decay
A
- observing action of lipase enzyme on milk sample made alkaline
- when lipase breaks down milk, pH decreases
- using phenolphthalein indicator, pink in alkalis, colourless in neutral and acidic
16
Q
Decay Practical
A
- measure 5cm^3 lipase solution into a test tube
- measure 5cm^3 milk into a separate test tube
- add 5 drops phenolphthalein indicator to the milk
- measure 7cm^3 sodium carbonate and add to milk test tube, should turn pink
- put both tubes in a water bath set 30°C
- place thermometer into tubes and wait till they reach 30°C
- once reached, use pipette to put 1cm^3 lipase solution into milk
- start stopwatch
- stir contents with glass rod
- stop timer when pink colour is lost then record time taken
- repeat with different temperatures
- can repeat and calculate mean
- calculate rate of decay
17
Q
Rate of decay formula
A
Rate = 1000/time
Unit of s^-1
