Decomposition & Decay

What is decomposition?

The breakdown of dead organisms and waste materials by decomposers.

What is a decomposer?

An organism that breaks down dead material and waste, releasing simpler substances.

Which organisms commonly act as decomposers?

Bacteria and fungi.

Why are decomposers important?

They recycle nutrients and chemical elements within ecosystems.

How do decomposers break down large biological molecules?

They secrete extracellular enzymes that digest material into smaller soluble molecules.

What is extracellular digestion?

Digestion occurring outside cells through enzymes released into the surroundings.

What happens to the products of extracellular digestion?

They can be absorbed and used by decomposers.

What happens to carbon during aerobic decomposition?

Decomposers respire and release carbon dioxide.

Why does decomposition contribute to nutrient cycling?

It returns mineral ions and other substances to the environment.

What happens to dead material if decomposers are absent or inactive?

It breaks down much more slowly.

Why does temperature affect decomposition?

It changes the activity of decomposer enzymes and the growth of microorganisms.

Why does moisture affect decomposition?

Decomposers require water for metabolic processes.

Why does oxygen availability affect decomposition?

Oxygen supports aerobic respiration by many decomposers.

Why can decomposition occur without oxygen?

Some microorganisms carry out anaerobic respiration or fermentation.

What is decay?

The decomposition of biological material by microorganisms and other processes.

Why does food spoil?

Microorganisms grow and break down the food, sometimes producing harmful substances.

How can refrigeration slow food decay?

Low temperatures reduce microbial growth and enzyme activity.

How can drying preserve food?

Removing water limits microbial growth.

How can freezing preserve food?

Very low temperatures greatly slow microbial activity.

Why is decomposition essential for plant growth?

It helps return mineral nutrients to the soil for plant uptake.