2. Autotrophs : self feeders, producers, produce organic molecules from CO 2 ◦ Photoautotrophs: light energy ◦ Chemoautotrophs: oxidize inorganic compounds i.e. sulfur or ammonia Heterotrophs : other feeding, rely on photoautotrophs for food & oxygen

3. Leaf Structure Chlorophyll – green pigment Mesophyll – tissue layer Stomata – pores for gas exchange Chloroplasts –Thylakoids –Grana –Stroma –Membranes

4. Summary equation : 6CO 2 + 12 H 2 0 + light energy → C 6 H 12 O 6 + 60 2 + 6H 2 0 Net: 6CO 2 + 6 H 2 0 + light energy → C 6 H 12 O 6 + 60 2 Simplified: CO 2 + H 2 0 + → CH 2 O + 0 2

5. Tracking Atoms (water is split) Photosynthesis: redox reaction, water split, electrons and hydrogen ions transferred to CO 2 reducing it to sugar.

6.  LIGHT REACTIONS ◦ Photolysis: splitting of water, oxygen waste ◦ Photophosphorylation: generates ATP ◦ Reduction of NADP + → NADPH  CALVIN CYCLE ◦ Carbon fixation (incorporation of CO 2 from atmosphere) ◦ Uses products of light reactions (ATP, NADPH) ◦ Light independent reactions

11.  Wavelength : distance between crests  Electromagnetic spectrum : range of radiation  Visible light : 380-750nm, detected by human eye  Photons : act like objects, fixed quantity of energy (inversely related to wavelength)  Spectrophotometer : measures light transmittance  Absorption spectrum : fraction of light not transmitted  Action spectrum : relative performance of different wavelengths  Pigments: chlorophyll a, chlorophyll b, carotenoids, xanthophyll, anthocyanin

12. Electromagnetic Spectrum

13. WHY ARE LEAVES GREEN? Chloroplast pigments absorb blue and red light and reflect or transmit green light.

14. INSIDE A SPECTROPHOTOMETER

18. PHOTOSYSTEMS: organized chlorophyll, proteins, sm. organic molecules. REACTION CENTER: chlorophyll a receives energized e- from other pigments, passes them to PRIMARY ELECTRON ACCEPTOR: traps high energy electrons.

20. NONCYCLIC ELECTRON FLOW

23. Generates equal amounts of ATP and NADPH Noncyclic photophosphorylation NONCYCLIC ELECTRON FLOW

26. Cyclic photophosphorylation No NADPH No oxygen released Generates more ATP for Calvin cycle CYCLIC ELECTRON FLOW

30. Light Reactions and Chemiosmosis: the organization of the thylakoid membrane

32.  Takes place in the stroma  3 Phases: carbon fixation, reduction, regeneration of RuBP  Requires ATP & NADPH from light rxns.  Involves carbon fixation (RuBP, CO 2 & rubisco)  Produces glyceraldehyde-3-phosphate (PGAL/G3P)  3 CO 2 yield 1 PGAL for glucose production Others used to recycle RuBP

37.  Light intensity – increase up to a point  Light wavelength – red or blue  Temperature of environment - ↑ up to a certain point  CO 2 levels - increase  H 2 O levels – slow down

38.  Bundle sheath cells have chloroplasts  Preface Calvin Cycle with 4-C acid (oxaloacetic acid) system  PEP (3-C) higher affinity for CO 2 than rubisco  Stomata closed - ↑ oxygen ↓ CO 2  Resist photorespiration – adapted to intense light & heat

39. Bundle sheath cells w/ chloroplasts Preface Calvin cycle w/ 4-C acid sys. Resist photorespiration Adapted for intense light & heat C 4 Leaf Anatomy

41.  Crassulacean acid metabolism  Succulents (water storing plants) cacti, pineapples  Open stomata at night, close during the day (helps conserve water)  At night they incorporate CO 2 into a variety of organic acids (store until later)  Day light → ATP & NADPH; CO 2 released and used in Calvin cycle