Learn: Photosynthesis

Welcome!Today we'll learn about photosynthesis, the process by which plants make their own food using sunlight. Let's explore how it works step by step!

What is Photosynthesis?Photosynthesis is the process by which green plants convert light energy, carbon dioxide, and water into glucose (a type of sugar) and oxygen. This is essential for the survival of plants and the life forms that depend on them.

The Word EquationThe word equation for photosynthesis is: Carbon dioxide + Water → Glucose + Oxygen. This shows the inputs and outputs of the process.

The Importance of PhotosynthesisPhotosynthesis is vital because it is how plants produce food and oxygen, which are necessary for life on Earth. Without photosynthesis, there would be no energy flow in food chains.

Conditions for PhotosynthesisPlants need three main conditions: light, carbon dioxide, and water. The process takes place in chloroplasts, which contain chlorophyll to absorb light energy.

Leaf AdaptationsLeaves are adapted for photosynthesis with features like a large surface area to capture sunlight, chloroplasts containing chlorophyll, and stomata for gas exchange.

Limiting FactorsThe rate of photosynthesis is affected by light intensity, carbon dioxide levels, and temperature. If any of these are insufficient, photosynthesis slows down.

Testing a Leaf for StarchTo check if photosynthesis has occurred, we test a leaf for starch. Starch is a storage form of glucose made during photosynthesis.

Steps in the Starch Test1. Boil the leaf in water to soften it.2. Place it in ethanol to remove chlorophyll.3. Rinse the leaf and add iodine solution. If it turns blue-black, starch is present.

Review Time!Great work! You've learned about photosynthesis, its conditions, adaptations, limiting factors, and how to test for starch. Let's review what you've learned with some final questions.