(a) Leaf surfaces contain stomata. (b) Carbon dioxide diffuses into leaves through stomata. Leaf surface 20  m Guard cells  Pore  Stoma Interior of leaf Stoma CO 2 Extracellular space Photosynthetic cells Leaf surface O2O2 H2OH2O

Wavelengths (nm) Shorter wavelength Longer wavelength Visible light Higher energy Lower energy Gamma rays X-rays Ultra- violet Infrared Micro- waves Radio waves

In plants, cells that photosynthesize typically have 40–50 chloroplasts Outer membrane Inner membrane Chloroplast 10  m 0.5  m Thylakoids (flattened sacs) Granum (stack of thylakoids) Stroma (liquid matrix)

FLUORESCENCE or Energy in electron is transferred to nearby pigment. Photon Chlorophyll  -carotene Chlorophyll and  -carotene molecules in antenna complex Chlorophyll molecule Photon Lower Higher Energy of electron Electron drops back down to lower energy level; heat and fluorescence are emitted. Electron is transferred to a new compound. REDUCTION/OXIDATION or RESONANCE Reaction center Fluorescence Heat 

Figure Higher Slide 6 Lower Energy of electron 4 Photons Photosystem II produced via proton-motive force 4 Photons Photosystem I Electron transport chain

Higher Photon Energy of electron Lower Photosystem I produced via proton-motive force P700

Chloroplast Stroma (liquid matrix) Granum (stack of thylakoids) Thylakoid membranes Cytochrome complex Photosystem IIPhotosystem IATP synthase Most abundant in the thylakoid membranes exterior to granum Most abundant in the thylakoid membranes of granum