Learn: Photosynthesis

Welcome!Today we'll learn about photosynthesis. It's an essential process that allows plants to make their own food using sunlight. Let's explore how it works step by step.

What is Photosynthesis?Photosynthesis is the process where plants use sunlight, carbon dioxide, and water to create glucose (a type of sugar) and oxygen. It’s vital because it provides food for plants and oxygen for animals to breathe.

The Photosynthesis EquationThe word equation for photosynthesis is: carbon dioxide + water → glucose + oxygen, with sunlight and chlorophyll playing key roles. Chlorophyll absorbs sunlight, and this energy drives the chemical reaction.

Leaf Structure and PhotosynthesisLeaves are specially designed for photosynthesis. They contain chloroplasts with chlorophyll, which traps sunlight. Their broad, flat surfaces help maximise light absorption.

Limiting Factors of PhotosynthesisPhotosynthesis can be affected by temperature, carbon dioxide concentration, and light intensity. If any of these is in short supply, the rate of photosynthesis slows down.

How Plants Use GlucosePlants use the glucose made in photosynthesis for respiration (energy), to produce starch (storage), and to make cellulose (for cell walls). Some glucose is converted into oils and proteins as well.

Investigating PhotosynthesisOne way to investigate photosynthesis is to test a leaf for starch. This shows whether photosynthesis has occurred. Leaves are boiled in ethanol to remove chlorophyll, then iodine is added to test for starch presence.

Review Time!Great work! You've learned about photosynthesis, its equation, limiting factors, leaf adaptations, and how plants use glucose. Let’s test your understanding with a few questions.