Photosynthetic organisms as producersSpec 6.1
In short
Photosynthetic organisms are plants and algae, which use light energy to make glucose from simple inorganic substances. This makes them the main producers of food and biomass, the mass of living material. Every food chain starts with a producer, and animals get their biomass, and the energy stored in it, by eating plants or algae or other animals.
Plants and algae carry out photosynthesis. They use light energy to make glucose from simple inorganic substances, so they do not need to eat other organisms.
This makes photosynthetic organisms the main producers of food and therefore of biomass. Biomass is the mass of living material. The glucose a plant makes is used to build new cells, so it becomes part of the plant's biomass.
Every food chain starts with a producer. Animals cannot make their own food, so they get their biomass, and the energy stored in it, by eating plants or algae, or by eating other animals that have eaten them.
- Producer
- An organism that makes its own food. Photosynthetic organisms (plants and algae) are the main producers of food and biomass.
- Biomass
- The mass of living material, which in a plant is made from the glucose it produces by photosynthesis.
Do not write that plants 'take in food' from the soil. Plants make their own food by photosynthesis. The roots take in water and mineral ions, not food.
Written and checked against the Edexcel GCSE Combined Science (1SC0) specification · Updated October 2026