Photosynthesis

Photosynthesis is where energy enters…

most of the food chains on Earth

Organisms that can carry out photosynthesis have…

crucial posiitions at the start of those food chains

How are plants able to make food?

Photosynthesis

What do photosynthetic organisms e.g. green plants and algae use energy to make?

They use energy from the sun to make glucose

What do some photosynthetic organisms use glucose to make?

Larger complex molecules that the plants or algae need to grow - these make up the organism’s biomass (the mass of living material)

What does the energy stored in the organisms’ biomass do?

It works its way through the food chain as animals eat them and each other

What are photosynthetic organisms?

The main producers of food for nearly all life on Earth

Where does photosynthesis happen?

Inside chloroplasts - they contain chlorophyll which absorbs light. Energy is transferred to the chlotoplasts by light

What is the word equation for photosynthesis?

Carbon dioxide + water -(light and chlorophyll)→ glucose + oxygen

What is the balanced symbol for photosynthesis?

6CO₂ + 6H₂O -(light and chlorophyll)→ C₆H₁₂O₆ + 6O₂

What type of reaction is photosynthesis?

An endothermic reaction - energy is taken in during the reaction

What is the rate of photosynthesis affected by?

By light intesntity, the concentration CO₂ and the temperature. Any of these 3 factors can become the limting factor (its stopping photosynthesis from happening any faster)

What is a limiting factor?

A variable of a system that causes a noticeable change in output or another measure of a type of system.

The temperature has to be…

just right for photosynthesis

How does temperature affect the rate of photosynthesis?

The temperature has to be just right, it affects the rate of photosynthesis because it affects the enzymes involved

What does it mean if the temperature is the limiting factor?

Because it’s too low - the enzymes needed for photosynthsis work more slowly at low temperatures

What happens if a plant gets too hot?

The enzymes it needs for photosynthesis and its other reactions will be dentatured - this happens at about 45°C (which is pretty hot for outdoors, although greenhouses can get that hot if you’re not careful)