Figure 14.26
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Transcript of Figure 14.26
Figure 14.26
Phototrophy
Figure 14.27
• To maximize light absorption, Halobacterium salinarium archaea pack their entire cell membrane with bacteriorhodopsin.
• - The protein forms trimers that pack in hexagonal arrays, forming the “purple membrane.”
• Each type of chlorophyll contains a characteristic chromophore, light-absorbing electron carrier.
Chlorophylls
- Chlorophyll molecules differ slightly in their substituent groups around the ring.
- These slight differences alter their absorption spectra.
Figure 14.29
Figure 14.31
• In purple bacteria, the efficiency of photon uptake is increased even more by the presence of thylakoids.
- Extensive backfolding of the photosynthetic membranes in oval pockets
Figure 14.32
Figure 14.35
Figure 14.34
Figure 14.33
Figure 14.36
• Animation: Oxygenic Photosynthesis
Click box to launch animation
Oxygenic Z Pathway
Overview of the Calvin CycleFigure 15.5
• Rubisco consists of small (S) and large (L) subunits.• - Catalyzes the condensation of CO2 to ribulose
1,5-bisphosphate, and the splitting of the unstable 6C intermediate into two 3C PGA molecules
Mechanism of Rubisco
Figure 15.6AB
• Many organisms contain the Rubisco complex within polyhedral structures called carboxysomes.
• The carboxysome takes up bicarbonate (HCO3–), which
is then immediately converted to CO2 by carbonic anhydrase.
Carboxysomes Contain Rubisco
Figure 15.8
- The CO2 is then fixed by Rubisco.