Photosynthesis

1
Photosynthesis

• Ch.2 Sec. 1

2
The Process

• 2 steps
• Happens in the chloroplasts
• Mostly in the leaves of plants

3
Step 1 Capture Energy

• Chloroplasts contain chlorophyll
• Green pigment
• Chlorophyll absorbs solar energy
• Like a solar panel

4
Step 2 Make Food

• Use energy from Step 1
• Also need water and CO2
• Water comes from soil
• Travels up from roots
• CO2 comes from air
• Enters through stomata

5
Stomata

• Small openings on the bottoms sides of leaves
• Allow O2 and water out
• Allow CO2 in
• Can open and close as needed

6
Stomata

7
Step 2 (contd)

• The energy from Step 1 is used to take apart the
  CO2 and H2O and recombine them as glucose
  (C6H12O6)
• O2 is produced as a byproduct

8
The equation

• CO2 H2O C6H12O6 O2

Light energy
9
The equation

• CO2 H2O C6H12O6 O2
• Balanced
• 6CO2 6H2O C6H12O6 6O2

Light energy
Light energy
10
The products

• Sugar glucose
• Used as food for energy
• Combined into starches to make cell walls
  cellulose
• Stored for later become part of plant

11
The products

• Oxygen
• Passes out through stomata
• Some used to break down sugar in mitochondria

12
The circle of life

• Plants and other organisms that do photosynthesis
  autotrophs
• Organisms that cant make their own food
  heterotrophs

13
The circle of life

• Heterotrophs get their energy
• by eating autotrophs
• Break down the stored sugar
• By eating heterotrophs that have eaten autotrophs

14
The circle of life

• All living things ultimately get their energy
  from the sun
• Food chain/web
• Sun?autotrophs?heterotrophs?other heterotrophs