1. Photosynthesis

2. Photosynthesis in Overview
(WHAT?) Process by which plants and other autotrophs store the energy of sunlight into sugars.
(HOW) Requires sunlight, water, and carbon dioxide.
Overall equation:
6 CO H2O + Light energy  C6H12O O2
(WHERE) Occurs in the leaves or stems of plants in organelles called chloroplasts.

3. Leaf Structure Most photosynthesis occurs in the palisade layer.
Gas exchange of CO2 and O2 occurs at openings in the leaf called stomata surrounded by guard cells on the lower leaf surface.
Palisade
Spongy

4. Chloroplast Structure
Inner membrane called the thylakoid membrane.
Thickened regions called thylakoids.
A stack of thylakoids is called a granum. (Plural – grana)
Stroma is a liquid surrounding the thylakoids.

5. Pigments
Chlorophyll A is the most important photosynthetic pigment. Absorbs blue-violet and red-orange light and reflects green light
Other pigments called accessory pigments are also present in the leaf.
Chlorophyll B
Carotenoids (orange / red)
Xanthophylls (yellow / brown)
These pigments are embedded in the membranes of the chloroplast in groups called photosystems and absorb maximum amount of light for photosynthesis to take place

7. Photosynthesis: The Chemical Process
Occurs in two main phases:
Light reactions
Dark reactions (aka – the Calvin Cycle)
Light reactions are the “photo” part of photosynthesis. Light energy is absorbed by pigments to split water molecules
Dark reactions are the “synthesis” part of photosynthesis. Trapped energy from the sun is converted to the chemical energy of sugars (carbohydrates).

8. Light Reactions
Light Reactions or Light-dependent reactions occur on the thylakoid membranes.
Light, carbon dioxide and water are required for this process.
Energy storage molecules are formed. (ATP and NADPH)
Oxygen gas is made as a by-product.

9. Dark Reactions (Calvin Cycle)
Dark reactions (light-independent) occur in the stroma.
Carbon fixation- Carbon dioxide is “fixed” into the sugar glucose.
ATP and NADPH molecules created during the light reactions power the production of this glucose.
Fun Fact! Anthocyanins (purple/red pigments) are produced in the fall in some plants

10. Purpose Importance of plants Renewable energy source
Refresher of atmosphere (provides abundant oxygen)
Habitat for countless organisms
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Example of beauty and majesty of creation