B14 Decomposition (triple only)

Question 1

What does decomposition mean?

Answer 1

Breakdown of dead materials into simpler organic matter

Question 2

How do decomposers breakdown dead material?

Answer 2

Decomposers release enzymes which catalyse the breakdown of dead material into smaller molecules

Question 3

Name factors that affect the rate of decomposition

Answer 3

Temperature
Water
Availability of oxygen

Question 4

Why is oxygen requited for decomposition?

Answer 4

Requited by most decomposers for aerobic respiration

Question 5

How does the availability of oxygen affect the rate of decomposition?

Answer 5

As oxygen levels increase the rate of decomposition increases

Question 6

Why can decomposition still occur in the absence of oxygen?

Answer 6

Some decomposers respire anaerobically

Question 7

Describe how soil water content affects the rate of decomposition?

Answer 7

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

Question 8

Describe how temperature affects the rate of decomposition?

Answer 8

Decomposers release enzymes
Rate highest at 50C (optimum)
Lower temperature enzymes work slowly therefore rate decreases
Higher temperature enzymes denature and decomposition stops

Question 9

How is the rate of decomposition calculated?

Answer 9

Rate of change = change in value/time

Question 10

Describe the conditions needed for rapid decay of watse biological material

Answer 10

Warm temperature - optimium temperature for enzymes

Oxygen - for aerobic respiraiton

Water - required for metabolism

Question 11

What is compost?

Answer 11

Nutrient rich product produced by rapid decomposition of dead plants and animal waste in optimum conditions.
Used by gardeners and farmers

Question 12

Why is compost used?

Answer 12

Natural fertiliser

Contains lots of minerals

Promotes growth of crops or garden plants

Question 13

Describe how biogas generators work

Answer 13

Produce methane

Due to anaerobic decomposition of animal waste

Methan is used as a fuel

Question 14

What happens to the pH when fresh milkj is decomposed?

Answer 14

Decreases

Question 15

What causes the decrease in pH when milk decomposes?

Answer 15

Proteins broken down into amino acids

Lipids broekn down into fatty acids

Fatty acids and amino acids decrease the pH