Daily Warm-up Tuesday, October 14th What are the two stages of photosynthesis? What happens in each? HW: -Read 8.3 and 8.4 Turn in: -Nothing

PHOTOSYNTHESIS!!!! Other organisms than just plants can photosynthesize. What about the endosymbiotic theory?

Modes of Nutrition Obtainment Autotrophs Heterotrophs What are fungi?

Photosynthesis and Energy Endergonic~ anabolic Light provides the energy to store the energy in the electrons.

Properties of Light

C

Pigments Chlorophyll Carotenoids Most common May broaden absorption spectrum Photoprotection What happens to electrons in chlorophyll?

Location of Photosynthesis Chloroplast Thylakoid Stroma

2 Stages of Photosynthesis 1. Light reaction (light-dependent) Takes place in thylakoids Requires water as electron donor Oxygen is released as a byproduct NADPH and ATP produced to be used by Calvin cycle 2. Calvin Cycle (light-independent) Sugars produced Takes place in stroma (fluid within chloroplast)

Light-Dependent Reactions Needs sunlight Produces water Makes ATP and NADPH Occurs in the thylakoids Photosystems Photosystem is cluster of proteins and chlorophyll- like a launch pad. Photosystem II and Photosystem I. 680 nm and 700 nm

Photosystem II Starting location of photosynthesis Pigments excited when light reaches them Electron passes through electron transport chain

Calvin Cycle Uses ATP and NADPH from light reactions to produce sugars Produces a 3-carbon sugar To do this, Calvin cycle must go around three times! Requires 3 molecules of CO2 Similar to Kreb’s cycle, but opposite in results.

Phases Phase 1: Carbon Fixation Attachment of carbon to pre-existing five-carbon sugar (RuBP) Enzyme that does this: Rubisco!!! Forms two 3-carbon sugars

Phase 2: Reduction ATP phosphorylates carbon molecule NADPH stores energy in the new form Becomes NADP+

Phase 3: Regeneration of CO2 Acceptor Making remaining carbon back into RuBP Loss of more ATP

Inputs and Outputs Light Reaction Input: Light Reaction Output: Water, light, NADP+ Light Reaction Output: ATP, oxygen, NADPH Calvin Cycle Input: ATP, NADPH, CO2 , RuBP Calvin Cycle Output: ADP, NADP+, 1 G3P G3P= glyceraldehyde 3-phosphate

Evolution of Photosynthesis C3 Plants C4 Plants CAM Plants C4 plants- make a 4-carbon sugar. Do better in hot areas CAM plants- open up stomata during the night only