Light energy can be transduced to reduce NADP+ to NADPH, and to supply energy for the accumulation of protons across the thylakoid membrane and into the thylakoid space. This occurs in algal protists and plants. (Bacteria have no chloroplasts, but they do sequester protons in one area.) The thylakoid membrane prevents protons from moving back across to the other side.
Now that everyone is partying it up in the stroma, it becomes the perfect location for the next stage of photosynthesis, the light-independent reactions.
Pictures are worth the thousand words that may or may not have just whizzed by your head as you were reading.
The Light-Dependent and Light-Independent Reactions
Keep in mind, water is the source of the electrons. As shown in this figure, electrons are removed from water in photosystem II, and consequently, these electrons become energized into a more energetic state. Protons and oxygen are released as by-products of this reaction.
The electron transport chain of respiration occurs in the mitochondria, whereas the electron transport chains of photosynthesis are located in the chloroplasts. The thylakoid membrane is home to the many proteins involved.
Light and dark reactions in photosynthesis - eschooltoday
Naturally occurring food and fuel contain complex carbon-based molecules, chiefly derived from plant matter that has been formed by photosynthesis. The chemical reaction of these molecules with oxygen releases energy; such reactions provide energy for most animal life and for residential, commercial, and industrial activities.
Energy IV - Photosynthesis (Light Reactions) | BIOL 110
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.)
Light-independent reactions - Wikipedia
In ordinary language, people speak of “producing” or “using” energy. This refers to the fact that energy in concentrated form is useful for generating electricity, moving or heating objects, and producing light, whereas diffuse energy in the environment is not readily captured for practical use. Therefore, to produce energy typically means to convert some stored energy into a desired form—for example, the stored energy of water behind a dam is released as the water flows downhill and drives a turbine generator to produce electricity, which is then delivered to users through distribution systems. Food, fuel, and batteries are especially convenient energy resources because they can be moved from place to place to provide processes that release energy where needed. A system does not destroy energy when carrying out any process. However, the process cannot occur without energy being available. The energy is also not destroyed by the end of the process. Most often some or all of it has been transferred to heat the surrounding environment; in the same sense that paper is not destroyed when it is written on, it still exists but is not readily available for further use.
Which reactions in photosynthesis require light? | …
Nuclear fusion is a process in which a collision of two small nuclei eventually results in the formation of a single more massive nucleus with greater net binding energy and hence a release of energy. It occurs only under conditions of extremely high temperature and pressure. Nuclear fusion occurring in the cores of stars provides the energy released (as light) from those stars. The Big Bang produced matter in the form of hydrogen and smaller amounts of helium and lithium. Over time, stars (including supernova explosions) have produced and dispersed all the more massive atoms, starting from primordial low-mass elements, chiefly hydrogen.