1. How do organisms get food?

2. Sun (solar or light energy)
Review:
Heterotrophs  organisms that cannot make their own food
Obtain food by:
Absorption: EX: decomposition – process by which fungi and some bacteria break own organic matter into a size and form that they can absorb for food
Ingestion: by mouth
Autotrophs  organisms that make their own food (producers)
Make food using ENERGY from… OR
Sun (solar or light energy)
Chemicals

3. Using energy from the sun to produce food is known as PHOTOSYNTHESIS.
All Plants
Some Bacteria
Occurs in the Chloroplast
Uses CO2 and H2O
Produces O2 and glucose (food)

5. Chlorophlast

6. Chloroplast Only found in autotrophs
Contain CHLOROPHYLL, a green pigment that traps light
LIGHT-DEPENDENT REACTION: Chlorophyll traps the sun’s light, and the light energy is converted into chemical energy called ATP (adenosine triphosphate)
Product: oxygen
LIGHT-INDEPENDENT REACTION: ATP is then converted into glucose using carbon dioxide.
Product: glucose

7. Factors that affect the rate of Photosynthesis
Carbon dioxide Concentration
Light
Temperature

8. So What?
On a global scale, photosynthesis is the most important process for the continuation of life on Earth.
Each year, photosynthesis makes 160 billion tons of carbohydrates.
21% of all atmospheric O2 results from photosynthesis in plants.
All the solid materials from every plant are built out of thin air…and all solid materials of every animal are built from plant materials.

9. Using energy from CHEMICALS to produce food is known as CHEMOSYNTHESIS
Requires no sunlight
Uses methane or sulfur
Occurs in places that do not receive sunlight, such as the deep sea vents.