Photosynthesis Overview HOMEWORK! READ CHAPTER 10…
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Transcript of Photosynthesis Overview HOMEWORK! READ CHAPTER 10…
Photosynthesis Overview
HOMEWORK! READ CHAPTER 10…
Stuff about photosynthesis you need to know
• Plants take sunlight energy to make carbohydrates!
• Electrons! They rule the world!– Take electrons from something?
• You take its energy!
• It usually falls apart!
– Give something electrons? • You give it energy!
• It makes the molecule bigger too!
Highlights!
• Plants use energy from the sun to make carbohydrates
• Photosynthesis uses water, carbon dioxide and sun-catching pigments.
• The process gives off oxygen
Photosynthesis is really two processes!
1. The light reactions 2. The Calvin Cycle
Calvin?
Light Reactions• Electrons from water
get put onto NADP+.• This makes NADPH
• Oxygen is released• H+ goes through ATP
synthase and makes ATP
Electrons are given to NADP+
Electrons from water
Oxygen leaves
photon
PigmentMakes NADPH
H+ goes through ATP synthase, makes ATPATP
So Far…
IN:• Water
• Sun
• NADP+
OUT:• Oxygen
• ATP
• NADPH
Calvin Cycle
• Takes NADPH, ATP, and CO2 to make carbohydrate! Often glucose: C6H12O6
More Specifically
• The electrons from NADPH get put onto CO2
• This takes energy from ATP!
• When electrons get added, CO2 becomes CH2O.. A small carbohydrate!~
Review
• Light reactions make NADPH, Oxygen, and ATP
• Calvin Cycle makes carbohydrate out of NADPH, CO2, and ATP
Photosynthesis
IN:• Water
• CO2
• Sunlight
OUT:• Oxygen• Carbohydrate
Oxidation/ReductionOxidation is loss (OIL)Reduction is gain (RIG)
Oxidation Reactions:
H2O to H+ and O2
NADPH to NADP+
Reduction Reactions
CO2 to CH2O
NADP+ to NADPH
CO2 + H2O + sun C6H12O6 + O2
(Carbon Dioxide) CO2 GETS REDUCED, makes CH2O (a small
carbohydrate.)
Oxidized or Reduced in Photosynthesis?
• H20• NADP+• NADPH• CO2
2H2O GOES TO 4H+ AND O2 IT IS OXIDIZED.
NADP+ GOES TO NADPH (REDUCED) IN THE LIGHT DEPENDANT REACTIONS
NADPH GOES TO NADP+ (OXIDATION) IN THE LIGHT INDEPENDENT REACTIONS (CALVIN CYCLE)
CO2 GOES TO CARBOHYDRATE IN THE LIGHT INDEPENDENT REACTION (REDUCTION.)
Wavelengths of light
•The pigments of photosynthesis work best in only a few wavelengths of light. (Green does not absorb green wavelengths of light. Chlorophyll is green.)
•Accessory pigments help absorb the wavelengths of light that are not absorbed by chlorophyll. Makes it so that photosynthesis can take place in any wavelength of light.
Absorption by pigments
Action spectrum
Photorespiration• Rubisco can grab O2 as easily as it grabs CO2.
• When rubisco grabs O2, it all falls apart, and they call this photorespiration.
• Because oxygen is made in the light reactions of photosynthesis, this is a problem.
• Future nobel prize winning research available…
1. C3 plants: photosynthesis like we learned. (Rubisco bonds to
CO2)2. C4 plants: CO2 gets fixed
onto PEP. PEP does not bond to oxygen…
3. CAM plants: CO2 gets stored in the mesophyll cells (inside part of the plant.)