Photosynthesis or How Plants Make Food

Plant Anatomy Chloroplast: organelle where photosynthesis takes place Chlorophyll: green pigment that absorbs the sun’s energy Thylakoid: flattened disks that contain chlorophyll Stroma: fluid surrounding the thylakoids Granum: stack of thylakoids

Which pigment contains the most energy? Pigment: absorbs light energy Different pigments absorb different wavelengths The color of the pigment is reflected, not absorbed All other colors are absorbed as energy Why are black t-shirts hotter to wear than white t-shirts?

Energy from the Sun is necessary to begin the process. Besides green plants, some algae and some bacteria can also make their own food.

Radiant energy from the Sun, in the form of photons, is absorbed by chlorophyll.

Hydrogen electrons found in the chlorophyll heat up and get very excited. These are known as the Light Reactions Because they Are dependent On the sun. They can only occur when the sun is out.

Once excited, these hydrogen electrons go through a series of reactions known as the Electron Transport Chain and make ATP. ADP + P  ATP (full of heat energy) (empty) Electrons get picked up by electron carriers and move into the stroma

Water is taken into the plant by the roots and carried to the leaves through the xylem. H20H20 H20H20 H20H20 Xylem is a series of tubes.

Plants need water… Photolysis: water is split to replace the hydrogen lost after the electron transport chain Oxygen is released as a waste product

Oxygen gas (O 2 ) is released into the atmosphere through the stomata on the under side of leaves. H20H20 H20H20 H20H20 O2O2 O2O2 O2O2

Carbon dioxide gas (CO 2 ) is taken into the plant through the stomata on the underside of leaves. H20H20 H20H20 H20H20 CO 2

Dark Reactions In the stroma, carbon dioxide, hydrogen and energy from ATP are combined to make glucose (C 6 H 12 O 6 ) This reactions do not Need the sun and can happen anytime

H20H20H20H20H20H20 CO 2 O2O2 O2O2 O2O2 H20H20 H20H20 H20H20 Review the process. Explain each step as it is shown.

H20H20H20H20H20H20 CO 2 O2O2 O2O2 O2O2 H20H20 H20H20 H20H20 Remember, this process is continuous in light.

Photosynthesis Equation When was carbon dioxide used? When was water used? When was oxygen made? When was glucose made?

Photosynthesis is important to all life on Earth. Plants and plant-like organisms replace oxygen used by animals when they breathe and us the carbon dioxide the animals exhale. The light energy from the Sun is converted into matter through a chemical reaction. The glucose produced is used both to keep the plants alive and stored to be used by animals that eat the plants. The animals convert the plant matter to chemical energy when the plants are digested and used a fuel by the animal.

Quiz Questions Which three types of organisms can produce their own food through photosynthesis? Why is photosynthesis necessary for life on Earth to continue? How do energy and matter interact in the photosynthesis process?