Download Section 4-1

Section 4-1
Photosynthesis
Sources of Energy
• Nearly all living things get their energy either
directly or indirectly from the sun.
– Photosynthesis: Process where the Sun’s energy is
converted to food in the chloroplasts of plants.
• Autotroph – An organism that makes it’s own
food (ex. Plants)
• Heterotroph – An organism that has to eat
other living things for energy.
Two Stages of Photosynthesis
• Stage One: Capturing Sun’s Energy
– A pigment called chlorophyll in the chloroplasts of plants
absorb the Sun’s energy
• Stage Two: Using the Sun’s energy to make food
• 6CO2 + 6H2O ----Sun Energy------> 6O2 + C6H12O6
• Carbon Dioxide + Water ----Sun Energy-----> Oxygen and Glucose
– Roots absorb water and stomata (small openings on the
undersides of leaves) take in carbon dioxide.
– Waste gas (oxygen) leaves the plant through the stomata.
– Glucose (food) is stored in the vacuole for later use.