PHOTOSYNTHESIS QUESTION 1986:              L. PETERSON/AP BIOLOGY

	Describe the light reactions of photosynthesis and, for both a C3 and a C4 plant,
	trace the path of a carbon dioxide molecule from the point at which it enters a
	plant to its incorporation into a glucose molecule. Include leaf anatomy and bio-
	chemical pathways in your discussion of each type of plant.


  STANDARDS:
  
  LIGHT REACHTIONS:                          Max. = 9 points
  __  Light required
  __  Light reactions on thylakoids (in grana)
  __  Cyclic and non-cyclic photophosphorylation/photosystems I & II
  __  H2O used/split/required
  __  Chlorophyll absorbs light
  __  Quality of light/color of light/wavelength of light must be correct
  __  Chlorophyll e-s excited/boosted to higher orbit
  __  Energy of e-s used to make ATP
  __  Chemiosmotic photophosphorylation/Mitchell hypothesis (proton gradient)
  __  Energy of e-s used to make NADPH+
  __  ADP or NADP used
  __  Carrier molecules for ATP or NADPH+ production
  __  Electrons of P700 replaced <- P680 (PSI <- PSII)
  __  Electrons of P680 replaced <- H2O   (PSII <- H2O)
  __  O2 comes from H2O
  __  O2 released to air
  __  Redox mentioned
  
  C3 AND C4 ANATOMICAL AND BIOCHEMICAL PATHWAYS:  Max. = 9 points
  __  CO2 enters through stomates
  __  CO2 diffuses from intercellular spaced into mesophyll
  __  Dark reaction/CO2 fixation in stroma (fluid)
  __  CO2 used/fixed/required
  __  Energy of ATP used
  __  Energy (e-s/Hs) of NADP reused
  __  C3 plants have palisade and spongy mesophyll
  __  C4 plants have functional mesophyll around bundle sheaths
  __  C4 plants have Kranz anatomy
  __  C4 plants have chloroplasts in bundle sheath cells
  __  C3 plants combine CO2 with RuBP
  __  C4 plants combine CO2 with PEP
  __  C4 plants use CAM pathway
  __  Steps in PEP -> 4-C -> PEP
  __  C4 plants send 4-C to bundle sheath
  __  C3 and C4 plants put CO2 into Calvin cycle -> glucose
  __  Steps in Calvin cycle
  __  Mention of C3, C4 pathway enzymes