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 8.5-1 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 400700600 500 400700600 500 400700600 500 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