1. photosynthesis song
photosynthesis song 2

2. photosynthesis video
Light Reaction Video

3. Autotrophs V. Hetertrophs
Heterotrophs
Organisms that CANNOT make their own food
Eat others
Animals

4. Autotrophs Organisms that make their own food
Plants, algae, some bacteria
Photosynthesis
Chemosynthesis

5. Photosynthesis
Converting light energy from the sun into chemical energy, which they then store primarily as glucose
Need:
Carbon Dioxide
Water
Light

6. Biochemical pathways
A series of chemical reactions in which the product from the first reaction is needed and consumed in the next
EX: Cellular Respiration (Auto/Heterotrophs)
Photosynthesis (Autotrophs)

7. Light Travels in waves of energy White: combo of visible spectrum
Visible Spectrum: ROY G. BIV ( R=longest…V=shortest)
Measured in wavelengths
Pigments absorb colors
Reflect what we see
Pigment: Molecules that absorb light

8. Why are plants green?
It’s the only color that doesn’t get absorbed by the pigments so our eyes see it.

9. Chloroplast

10. Thylakoid Membrane:
discs that contain pigment; all
light capture occurs here
Grana: stacks of thylakoids
Stroma: gel like substance that surrounds

11. Pigments
Chlorophyll a: only one involved in PS I and PS II; main pigment
Accessory pigments: aid in light capture; absorb different wavelengths; more efficient; fall (amt. sun)
1. chlorophyll b
2. carotenoids ( yellow, orange, brown)
3. xanthophylls (yellow green)
4. Anthocyanin (red)
Other pigments show up in the fruits/flowers

12. Photosynthesis
What is it???
Occurs in 2 reactions: Light & Dark

13. Light Reaction Needed to fuel Dark Reaction (biochemical pathway) 2 parts
Light Capture
2. Electron Transport Chain

14. Light Capture (Sunlight)
1st step in photosynthesis
Accesssory pigments and chlorophyll a capture light ( in the form of bonds)
Light E is the fuel!!!!
Chloroplast(thylakoid membrane)

16. Electron Transport Chain 2 parts 1. Photosystem I 2. Photosystem II
Electron Transport Chain song
Occurs b/c water splits and ELECTRONS are FREE!

17. Steps of ETC (Water) Photosystem I
Chlorophyll a absorbs light E (photon)…electron become excited
Electrons are boosted to next E level leave chlorophyll a (oxidation)
PEA (primary electron acceptor) accepts electron (reduction)
PEA donates e to stroma
Electron combine with NADP & protons
Result: NADPH

20. Steps ETC (p.2) Photosystem II
Chlorophyll a continues to capture light & replace lost electrons…allows reaction to continue (fuels it)
Water splits===free electrons and Oxygen
Chemiosmosis: synthesis of ATP; electrons combine with ADP

21. Result of Light Reactions
2 ATP 1 NADPH light reactionl These will be used to fuel Dark Reactions !!!!! (biochemical pathway)

22. The Dark Reaction (CO2…)
AKA Calvin Cycle
Occurs in the Stroma
CO2 enters through the stoma on the leaf)
Remember: Hydrogen protons build up in thylakoid membrane from water splitting…pumped into stroma (active transport)..this creates a concentration gradient (draw picture)
Goal of photosynthesis: capture Carbon atoms from carbon dioxide and use them to make sugar (glucose) equation:

23. Carbon fixation Incorporation of carbon into organic molecules
Occurs during Calvin Cycle
Carbon from carbon dioxide

24. Calvin Cycle Powered by ATP and NADPH (from light rxn)
Goal= glucose from carbon
Carbon dioxide diffuses into stroma from cytosol

25. Steps: 1. Carbon dioxide diffuses into the stroma from the cytosol
2. PGAL, a 3 carbon molecule, is converted into PGAL, another 3 Carbon molecule.
ADP, NADP, and phosphate are also produced and can be used in the light reactions.
3. RuBP made

26. For every turn of the Calvin Cycle the following is produced:
1 ATP 1 PGAL (3 turns) USES: 2ATP 2NADPH

27. Equation

28. Dark reaction
Photosynthesis overview

29. Use what you’ve learned about photosynthesis to explain the humor in this cartoon.

30. Rate of Photosynthesis
Light Intensity: increase l.i. increase rate initially then levels off
Carbon Dioxide: increase rate initially
Temperature: increase accelerates chemical reactions therefore increasing rate.
Temperature: too high stops photosynthesis b/c stomata close not allowing carbon dioxide in or water out.