Photosynthetic efficiency - Wikipedia

The energy released by burning fuel or digesting food was once energy from the sun that was captured by plants in the chemical process that forms plant matter (from air and water). (Boundary: The fact that plants capture energy from sunlight is introduced at this grade level, but details of photosynthesis are not.)

Energy efficiency of photosynthesis - Encyclopedia …

approximate efficiency of the conversion of light energy to chemical ..

What Is Photosynthesis? From Light Energy to Chemical Energy

Photosystem II (PSII) initiates photosynthesis in plants through the absorption of light and subsequent conversion of excitation energy to chemical energy via charge separation. The pigment binding proteins associated with PSII assemble in the grana membrane into PSII supercomplexes and surrounding light harvesting complex II trimers. To understand the high efficiency of light harvesting in PSII requires quantitative insight into energy transfer and charge separation in PSII supercomplexes. We have constructed the first structure-based model of energy transfer in PSII supercomplexes. This model shows that the kinetics of light harvesting cannot be simplified to a single rate limiting step. Instead, substantial contributions arise from both excitation diffusion through the antenna pigments and transfer from the antenna to the reaction center (RC), where charge separation occurs. Because of the lack of a rate-limiting step, fitting kinetic models to fluorescence lifetime data cannot be used to derive mechanistic insight on light harvesting in PSII. This model will clarify the interpretation of chlorophyll fluorescence data from PSII supercomplexes, grana membranes, and leaves.

The maximum efficiency of photosynthesis (PDF …

Nuclear fusion can result in the merging of two nuclei to form a larger one, along with the release of significantly more energy per atom than any chemical process. It occurs only under conditions of extremely high temperature and pressure. Nuclear fusion taking place in the cores of stars provides the energy released (as light) from those stars and produced all of the more massive atoms from primordial hydrogen. Thus the elements found on Earth and throughout the universe (other than hydrogen and most of helium, which are primordial) were formed in the stars or supernovas by fusion processes.

05/04/2010 · Best Answer: The photosynthetic efficiency is the fraction of light energy converted into chemical energy during photosynthesis in plants and algae.

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We'll look at a simpler example of photosynthesis first, and use it as an introduction to photosynthesis in plants and cyanobacteria (blue-green algae). Although the primary reactions of photosynthesis take place at "photosynthetic reaction centers," the first level of interaction of light with an organism that carries out photosynthesis is at an assembly of chlorophyll molecules that "harvest" light (the "light-harvesting complex"). Such an assembly results in a greater chance that photons will be captured and, because of the strategic arrangement of the individual chlorophyll and other accessory light-absorbing molecules, the transfer of energy to the photosynthetic reaction center is very fast (-10 s) and very efficient (>90%).

The photosynthetic efficiency is the fraction of light energy converted into chemical energy during photosynthesis in plants and algae

American Energy Independence and America's Solar Energy Potential

During photosynthesis, a process that occurs in plants and in cyanobacteria and also in purple photosynthetic bacteria, light energy is converted into chemical energy. The overall process is described by the chemical equation:

Photosynthesis is a process used by plants and other organisms to convert light energy, normally from the sun, into chemical energy that can be used to fuel the

The reaction center is in the thylakoid membrane

You have already studied the "dark reaction" and I will refer you to Dr. Diwan's notes on the subject. As the overall process of photosynthesis involves a series of electron transfer reactions, we are in the realm of oxidation-reduction chemistry, and it would help to review the basics of these processes because we will be going into this topic in greater depth. There is a direct analogy to electron transfer in the mitochondrion, in which clumps of energy are transferred from one electron carrier to another along a "chain" and H+ ions are translocated out, across the mitochondrial membrane, thus generating an electrochemical gradient. The energy inherent in this gradient is used to synthesize ATP in the process of "oxidative phosphorylation." The same processes occur in photosynthesis and the chloroplast, the site of photosynthesis in plants and blue-green algae (but not in photosynthetic bacteria), is the analog of the mitochondrion in eukaryotes.

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The first step in photosynthesis is the interaction of light with chlorophyll molecules. The chemical structures of the various chlorophyll molecules are based upon the cyclic tetrapyrrole that is also seen in the heme group of globins and cytochromes. Various modifications of this group, namely ring saturation characteristics and substitutions on the rings provide a series of pigment molecules that, as a group, absorb effectively over the wavelength range of 400 nm - 700 nm, the spectrum of . It is the high degree of conjugation of these molecules that makes them so efficient as absorbers of visible light.