1. PHOTOSYNTHESIS

2. All plants need
Sun
Water
CO2

3. Plants give us O2
Food

4. Review
Everything that goes into a chemical reaction (reactants) must come also come out (products).

5. Apply it
Photosynthesis is a chemical process that occurs in the chloroplasts of plant cells.

6. All plants need
Sun
Water
CO2
REACTANTS

7. Plants give us O2
Food
PRODUCTS

8. We’re almost done with that equation, but need to tweak it a little…
carbon dioxide + water + sun food + oxygen
C6H12O6
(nrg)
nrg O2
CO2 +
H2O + +
We’re almost done with that equation,
but need to tweak it a little…

9. Balanced equations have the same number of molecules on each side of the arrow (reactants and products). So, let’s balance it…
6CO2 +
6H2O
nrg
C6H12O6
6O2

10. 4. How Does it Work?
Plants absorb the suns’ energy with molecules called PIGMENTS.
The primary pigments in plants are chlorophyll a and b.

11. 5. Where does it happen?

12. STEP 1 – Light Dependent Rxns.
6. A two step process:
STEP 1 – Light Dependent Rxns.
Need: energy from sun, ADP, water
Give off: ATP and Oxygen
Happens in the thylakoid membranes

13. Step 2 – Light Independent Rxns.
6. A two step process
Step 2 – Light Independent Rxns.
Need: ATP and carbon dioxide
Give off: ADP and glucose
Happens in the stroma

14. 6. The two steps Light Dep. Light Indep. Need: nrg, ADP, H2O ATP, CO2
Give: ATP, O ADP, C6H12O6
Remember that equation?
6CO2 + 6H20+ sun(nrg) C6H O2
(nrg)

15. 6. The two steps Light Dep. Light Indep. Need: nrg, ADP, H2O ATP, CO2
Give: ATP, O ADP, C6H12O6
Remember that equation?
6CO2 + 6H20+ sun(nrg) C6H O2
(nrg)

16. 7. What affects photosynthesis?
Water
Water up, photosyn. Up
Water down, photosyn. Down
Plants need to adapt to conserve water (waxy coatings, spines)

17. 7. What affects photosynthesis?
Temperature
If temp is too high or too low, photosyn. slows or stops
Enzymes control photosynth. and enzymes work within a range of temps (0-35°)

18. 7. What affects photosynthesis?
Intensity
Light intensity up, rate up
Only to a point, then no more

19. Ta-da….you have covered photosynthesis!