1. Photosynthesis
process by which plants, algae and some bacteria use light energy to convert inorganic compounds into organic compounds

2. Overall Reaction light enzymes CO2 + H2O → → → C6H12O6 + O2
Inorganic    Organic
Reverse of cellular respiration

3. Plants use glucose to:
generate ATP molecules during cellular respiration ( Plants carry out respiration too)
build more complex organic molecules
→ fats (oils, waxes)
→ starch
→ proteins
→ nucleic acids (DNA and RNA)

4. Importance of Photosynthesis
food source for other organisms
provides oxygen gas in atmosphere

5. Site of Photosynthesis: Chloroplast

6. Why are plants green?

7. Chloroplast
Grana: stacks of thylakoids that contain chlorophyll ( Light Reaction )
Stroma: thick fluid that suspends the grana ( Dark Reaction)
Chloroplasts, like mitochondria, have a double membrane

9. Light Waves Light is composed of photons of energy that travels in waves The wavelength of light determines its color.

10. Electromagnetic Spectrum
ROYGBIV

11. Plants absorb most wavelengths of light except green
Green light waves are reflected – which is why plants look green

12. Photosynthetic Pigments
Chlorophyll is the most abundant (PSP)
chlorophyll a & b absorb red and blue light, reflect green light

13. Photosynthetic Pigments

14. Photosynthetic Pigments
having several types of pigments in a leaf allows the plant to absorb more of the light
In this way more energy is available for photosynthesis

15. Photosynthesis Light reactions: occur in the grana
There are two stages ( Reactions )
Light reactions: occur in the grana
( Splits H2O and make ATP )
Dark reactions (Calvin cycle): occur in the stroma
(Makes G3P -a precursor to glucose)

16. Structure of a Chloroplast
The light reactions take place in the thylakoid membrane
The dark reactions take place in the stroma

18. Stage I - Light Reaction
Also called Light Dependent Reaction
Pigments in the chloroplasts intercept light and begin the light reactions of photosynthesis.
Photosystem: a unit of several hundred chlorophyll a molecules and associated acceptor molecules

19. Photosystems
when a photon strikes a pigment molecule, the energy jumps from pigment to pigment until it reaches the reaction center

20. Photosystems

21. Photosystems water molecules are split using light energy
This is called photolysis → releases O2 in the atmosphere

22. Two Types of Photosystems
Photosystems Produce a small amount of ATP and NADPH

24. Photosynthesis Animations

25. Stage II: Dark reactions (Calvin Cycle)

26. Dark Reactions (Calvin Cycle)
Using carbon from CO2 (Low Energy and Inorganic) and the ATP, NADPH, from the light reaction
Calvin cycle synthesizes an energy-rich sugar molecule (glyceraldehyde 3-phosphate or G3P)
G3P is a raw material used to make glucose and other organic molecules

27. Calvin Cycle

28. Calvin Cycle For every 3 CO2 used, 1 G3P is formed
Photosynthesis Fill In Quiz
Respiration & Photosynthesis Quiz