Presentation on theme: "Chapter 8 Light and Pigments. Need To Know How photosystems convert light energy into chemical energy. (There will be more on this in the next couple."— Presentation transcript:
Chapter 8 Light and Pigments
Need To Know How photosystems convert light energy into chemical energy. (There will be more on this in the next couple of days.)
Figure Light H2OH2O Chloroplast Light Reactions P i ADP NADP O2O2 ATP NADPH CO 2 Calvin Cycle Two Stages of Photosynthesis Calvin Cycle [CH 2 O] (sugar)
Figure 8.15 Electron transport chain Higher [H ] P i HH CHLOROPLAST STRUCTURE Inter- membrane space MITOCHONDRION STRUCTURE Thylakoid space Inner membrane Matrix Key Lower [H ] Thylakoid membrane Stroma ATP synthase ADP HH Diffusion
Figure 8.9 Chloro- phyll a Rate of photosynthesis (measured by O 2 release) Results Absorption of light by chloroplast pigments Chlorophyll b Carotenoids Filament of alga Aerobic bacteria (a) Absorption spectra (b) Action spectrum (c) Engelmann’s experiment Wavelength of light (nm)
Figure 8.10 Hydrocarbon tail: interacts with hydrophobic regions of proteins inside thylakoid membranes of chloroplasts; H atoms not shown Porphyrin ring: light-absorbing “head” of molecule; note magnesium atom at center CH 3 in chlorophyll a CHO in chlorophyll b CH 3 A slight structural difference between chlorophyll a and chlorophyll b causes them to absorb slightly different wavelengths.
Figure 8.11 Photon (fluorescence) Ground state (b) Fluorescence Excited state Chlorophyll molecule Photon Heat e−e− (a) Excitation of isolated chlorophyll molecule Energy of electron