Chloroplasts bioenergetics

Ozone has been shown to initiate many physiological and biochemical changes in sensitive plant species. Decreases in photosynthesis and increases and decreases in respiration have occurred in response to ozonation. The bioenergetic status of mitochondria and chloroplasts is disturbed by ozone. Decreases in oxidative- and photo- phosphorylation have been reported as have increases in adenosine triphosphate and total adenylate content of plant tissue. The variable physiological responses appear to be related to the stage of symptom development at the time of analysis and to the mode of ozone exposure, viz. in vivo and in vitro. 

Figure 6-7. Schematic representation of the interrelationships among components involved in chloroplast and mitochondrial bioenergetics.

Racket, E. (1980) From Pasteur to Mitchell A hundred years of bioenergetics. Fed. Proc. 39, 210-215. Bogorad, L. (1981) Chloroplasts. J. Cell Biol. 91, 256s-270s. 

EG Uribe and CY Li (1973) Stimulation and inhibition of membrane-dependent ATP synthesis in chloroplasts by artificially inducedK gradients. Bioenergetics 4 435-444... 

Greenbaum E 1989 Biomolecular electronics observation of oriented photocurrents by entrapped platinized chloroplasts Bioelectrochem. Bioenerget. 21 171-7... 

In addition to the presence of PBSs, cyanobacteria are also distinct from eukaryotic chloroplasts with respect to respiratory and photosynthetic electron transport. Both bioenergetic processes function within the thylakoid membrane of cyanobacteria, and thus share a common PQ pool and a common Cyt bi/f complex (Scherer, 1990 ... 

Peter Mitchell His chemiosmotic hypothesis, wherein ATP was synthesized by an electrochemical gradient of hydrogen ions across bacterial, mitochondrial, and chloroplast membranes, revolutionized bioenergetics. 

In bioenergetics the basic unit of action is the cell and its organelles (e,g, chloroplast and mitochondria) of which the cell s plasma membrane along with its organelle membranes play the central role. For a cell to be viable, nutrients and toxic waste products must be transported across the membrane, for which AG must be negative otherwise metabolic energy must be supplied. 

Peters RLA, Bossen M, van Kooten 0 and Vredenberg WJ (1983) On the correlation between the activity of the ATP-hydrolase and the kinetics of the flash-induced P515 electrochromic bandshift in spinach chloroplasts. Journal of Bioenergetics and Biomembranes (in press). 

Nelson N (1981) Proton-ATPase of chloroplasts. In Current topics in bioenergetics, Sanadi DR and Vernon LP,eds. vol.ll, p. 1-33, Academic Press, New York... 

Roos P, Berzborn RJ (1982) Is subunit 6 indeed required for CF binding to the chloroplast membrane in Proc. 2nd Europ. Bioenergetics Conf., Lyon-Villeurbanne, CNRS ed. pp. 99-100... 

M. Avron. Photoinduced electron transport in chloroplasts. Current Topics in Bioenergetics, 2 1—22, 1967. 

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