Decay

Question 1

decay/decomposition

Answer 1

the breakdown of materials by microorganisms

Question 2

rate of decomposition

Answer 2

mass lost / number of days

Question 3

decomposers

Answer 3

cause soft tissue of organisms to decay soon after death

grow best in warm, moist conditions with enough oxygen

Question 4

what is the rate of decomposition affected by?

Answer 4

• warm temperatures
• this increases enzyme activity in microorganisms
• water content
• microorganisms need water for many cell processes to work
• oxygen availability
• many microorganisms need oxygen for respiration

Question 5

preventing decay (3)

Answer 5

refrigerating food
-foods lasts longer because the temperature is too cold for most microorganisms to grow quickly

salting food
-lasts longer because it causes water to move out of the bacteria cells by osmosis, so there is not enough water in the microorganisms for respiration

packing food in nitrogen
-makes it last longer because there is no oxygen for microorganisms to respire

Question 6

recycling kitchen and garden waste

Answer 6

can be used to make compost, in the garden or by council schemes

conditions should be controlled to ensure the growth of decay microorganisms, which grow and digest faster in moist, warm and aerobic conditions