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 reactions2.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 Pigment Makes NADPH H+ goes through ATP synthase, makes ATP ATP
So Far… IN: Water Sun NADP+ OUT: Oxygen ATP NADPH
Calvin Cycle Takes NADPH, ATP, and CO 2 to make carbohydrate! Often glucose: C 6 H 12 O 6
More Specifically The electrons from NADPH get put onto CO 2 This takes energy from ATP! When electrons get added, CO 2 becomes CH 2 O.. A small carbohydrate!~
Review Light reactions make NADPH, Oxygen, and ATP Calvin Cycle makes carbohydrate out of NADPH, CO 2, and ATP
Photosynthesis IN: Water CO 2 Sunlight OUT: Oxygen Carbohydrate
Oxidation/Reduction Oxidation is loss (OIL) Reduction is gain (RIG) Oxidation Reactions: H 2 O to H+ and O 2 NADPH to NADP+ Reduction Reactions CO 2 to CH 2 O NADP+ to NADPH
CO 2 + H 2 O + sun C 6 H 12 O 6 + O 2 (Carbon Dioxide) CO 2 GETS REDUCED, makes CH 2 O (a small carbohydrate.)
Oxidized or Reduced in Photosynthesis? H 2 0 NADP+ NADPH CO 2 2H 2 O GOES TO 4H+ AND O 2 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.)