Explain thermodynamics in the process of photosynthesis.
Answers
ANSWER
The thermodynamics of photosynthesis has been much discussed, but recent articles have pointed to some confusion on the subject. The aim of this review is to clarify a limited part of this state of affairs.
Early discussions of the thermodynamics of photosynthesis concluded that the efficiency is inherently limited (Duysens 1958; for a good review see Knox 1969). More recently, Lavergne and Joliot (2000) proposed a similar efficiency limit of ~70 % based on the Carnot cycle and a “temperature” of ~1,100 K for the excited state of chlorophyll. However, Parson (1978) had already argued that the Carnot cycle was not applicable and that the kinetics of the species determined the efficiency. Jennings et al. (2005) have reviewed this literature and come down on the side of Parson but with rather distressing conclusions on the violation of the second law of thermodynamics. This has been refuted by Lavergne (2006) and by Knox and Parson (2007). Jennings et al. (2007) disagree but offer no refutation. I believe Lavergne and Knox and Parson are correct, but their arguments are based on implicit assumption of equilibrium between radiation and the excited state. The limited aim of this review is to discuss the efficiency of the primary reactions of photosynthesis. This is critical since the overall yield completely depends on the initial yield.
Answer:
. A procedure by which the initial state of a system changes to its final state is called a thermodynamic process. During the process, there may be (i) addition of heat to the system (i) removal of heat from the system (ii) change in the temperature of the system (iv) change in the volume of the system (v) change in the pressure of the system.