1. Photosynthesis
Chapter 10

2. Respiration
Photosynthesis

3. I) Photosynthesis A) Equation:
CO2+H2O C6H12O6 + O2
B) Occurs in the chloroplasts using the enzymes chlorophyll

4. C) Broken into 2 parts: 1) Calvin Cycle (light independent reaction): a) occurs in the stroma of chloroplast

5. 2) Light reaction a) occurs in the thylakoid membrane a1) fyi: stacks of thylakoids are called grana

6. D) Fate of the reactants 1) CO2+H2O C6H12O6 + O2
a) using heavy O, they traced where the elements ended up:
CO2+H2O C6H12O6 + O2

7. II) Properties of light
A) Electromagnetic spectrum a) red is weakest(longest wavelength 750nm) b) violet is strongest(shortest wavelength 380nm)

8. B) Absorption spectrum: areas of visible spectrum that is absorbed by a pigment 1) specific wavelengths(photons) are absorbed by a particular pigment

9. a) absorbed means it has enough energy to cause an electron to jump from a lower energy level to a higher one.

10. a1) with no-where to go the excited electron will fall back to original orbital, emitting light(fluorescence)

11. a2) chloroplasts use a primary electron acceptor molecule to trap the excited electron and use it to make NADPH and ATP instead of losing energy as light and heat

12. b) Pigments: b1) chlorophyll a: only pigment that passes electrons directly to the primary electron acceptor

13. b2) chlorophyll b: pass excited electrons to chlorophyll a

14. b3) Carotenoids: yellows and oranges
b3) Carotenoids: yellows and oranges * do absorb light and pass electrons to chlorophyll * serve in photoprotection: absorb excessive light that may damage chlorophyll

15. * xanthophylls: contain oxygen * carotenes: pure hydrocarbons

16. C) Action spectrum: region of visible spectrum that does the work(measured by O2 release).

17. III) The Light reaction
A) Photosystems 1) groups of pigments that pass electrons along to a chlorophyll a molecule, which is directly associated with a primary electron acceptor

18. a) Photosystem I(P700) a1) named after wavelength absorbed by the chlorophyll a associated with the electron acceptor

19. a2) photosystem II(P680): this cholorphyll a absorbs a wavelength of 680nm

20. The Light Reaction: The “Z” scheme with non-cyclic photophosphorylation

21. The Light Reaction: Cyclic-photophosphorylation
Purpose:

22. B) Chemiosmosis
ATP production from the light reaction:

23. IV) The Calvin Cycle (light independent reaction)
A) CO2’s go in, 3-carbon sugars(G3P) come out, which are then assembled into glucose and other organic compounds

24. 1) Driven by the re-use of a 5 carbon sugar called Ribulose bisphosphate

25. a) Enzyme called rubisco attaches a CO2 to ribulose bisphosphate, making a 6-C sugar that splits in two, which chugs through the rest of the cycle

26. V) Other forms of carbon fixation
A) “Standard”: C3 plants 1) use rubisco in the Calvin cycle, making 3- carbon sugars after the initial carbon fixation phase

27. 2) dependent on open stomata to provide CO2. No CO2 – no Calvin cycle

28. B) C4 Plants
1) Contain a layer of bundle sheath cells between the vascular tissue and the mesophyll

29. 2) mesophyll cells use the enzyme PEP carboxylase to add CO2 to PEP(3C) to make oxaloacetate(4C).

30. 3) This changes to Malate(4C) which diffuses into a bundle sheath cell and drops off a CO2, which will then go into the calvin cycle

31. a) this keeps CO2 concentration high in the bundle sheath cell so O2 won’t be able to bind rubisco

32. C) CAM plants
1) adaptation in succulents and cacti, among other plants

33. 2) Make organic acids during the night, close their stomata during the day, and cut CO2 from the organic acid to pump into the calvin cycle

34. 3) compared to C4, C4 plants separate steps spatially, while CAM plants separate the steps temporally.