Light-triggered electron

Fig. 14 Light-triggered electron transfer, monitored by photomodulated amperometry.

The minimum energy needed to remove an electron from a potassium metal surface is 3.7 X 10 J. Will photons of frequencies 4.3 X 10 s (red light) and of 7.5 X 10 s (blue light) trigger the photoelectric effect If so, what is the maximum kinetic energy of the ejected electrons ... 

The reconstituted photoactive proteins may act as light-triggered cofactors, activating enzyme cascades. For example, the electron-transporting protein cytochrome... 

Schlodder E and Witt HT (1981) Relation between the initial kinetics of ATP synthesis and of conformational changes in the chloroplast ATPase studied by external field pulses. Biochim. Biophys. Acta 635, 571-584. Schumann J and Strotmann H (1981) The mechanism of induction and deactivation of light-triggered ATPase, In Photosynthesis II. Electron Transport and Photophosphorylation, (ed. G Akoyunoglou) pp. 881-892. Balaban, Philadelphia... 

Schumann J and Strotmann H (1981) The mechanism of induction and deactivation of light-triggered ATPase in Akoyunoglou,G. Photosynthesis II. Electron transport and photophosphorylation pp. 881-892 Balaban Int. Science Services, Philadelphia Pa. 

The present discussion is only concerned with the structure/redox capacity of the site responsible for the oxidation of water. The starting point is the evidence that the photosynthetic pathway is triggered by photooxidation of the chlorophylls in photosystem II. The need for chlorophylls to recover the electrons lost in photooxidation (in order to regenerate their ability to absorb light) induces water to undergo oxidation, according to ... 

Most mechanisms which control biological functions, such as cell respiration and photosynthesis (already discussed in Chapter 5, Section 3.1), are based on redox processes. In particular, as shown again in Figure 1, it is evident that, based on their physiological redox potentials, in photosynthesis a chain of electron carriers (e.g. iron-sulfur proteins, cytochromes and blue copper proteins) provides a means of electron transport which is triggered by the absorption of light. 

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