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en.wikipedia.org/wiki/Light-dependent_reactions

In photosynthesis, the light-dependent reaction takes place on the thylakoid membranes. ... Cyclic phosphorylation is important to create ATP and maintain NADPH in the ... It transfers light energy to a dimer of chlorophyll pigment molecules near the ... The energy, but not the e- itself, can be passed onto another molecule.

en.wikipedia.org/wiki/Facilitated_diffusion

Facilitated diffusion is the process of spontaneous passive transport of molecules or ions across a biological membrane via specific transmembrane integral proteins. Being passive, facilitated transport does not directly require chemical energy from ATP hydrolysis in the transport step itself; rather, molecules and ... Facilitated diffusion is different from free diffusion in several ways.

www.khanacademy.org/science/biology/energy-and-enzymes/atp-reaction-coupling/a/atp-and-reaction-coupling

ATP structure, ATP hydrolysis to ADP, and reaction coupling. ... Even if they would not be energetically favorable (energy-releasing, ... However, if the energy runs out, the reactions will grind to a halt, and the cell will ... Often, the "payment" reaction involves one particular small molecule: adenosine triphosphate, or ATP.

www.khanacademy.org/science/biology/energy-and-enzymes/the-laws-of-thermodynamics/a/the-laws-of-thermodynamics

An open system can exchange both energy and matter with its surroundings. ... drink cooler with a lid is conceptually similar to a true isolated system. ... In this regard, they are no different from energy transfers in, say, an electrical circuit. .... The net effect of the original process (local decrease in entropy) and the energy ...

www.khanacademy.org/science/biology/membranes-and-transport/active-transport/a/active-transport

However, because atoms and molecules can form ions and carry positive or negative ... Secondary active transport (cotransport), on the other hand, uses an ... and thus does not directly require a chemical source of energy such as ATP. .... for only a tiny fraction of the sodium-potassium pump's effect on membrane potential.

community.tncc.edu/faculty/zahn/mypage/cell_respiration.htm

This process of converting energy in the food we ingest into energy in ATP requires oxygen. Think about that; every cell in your body has to do this for itself. Cells can cooperate to get the oxygen to other cells, but nor cell can make ATP and ... Glycolysis--The breakdown of a glucose molecule into two three-carbon pieces ...

www.britannica.com/science/adenosine-triphosphate

Adenosine triphosphate, (ATP), energy-carrying molecule found in the cells of all ... processes by transferring a phosphate group to another molecule (a process ... at which chemical reactions proceed without itself being altered in the process. ... Take this General Science True or False Quiz at Encyclopedia Britannica to ...

www.ncbi.nlm.nih.gov/books/NBK26894

Without mitochondria, present-day animal cells would be dependent on anaerobic ... In others they remain fixed in one position where they provide ATP directly to a site of ... Such molecules can enter the intermembrane space, but most of them ... These high-energy electrons are then transferred to the inner mitochondrial ...

www.ncbi.nlm.nih.gov/books/NBK26838

In other reactions, these small molecules are being used to construct an ... Each cell can be viewed as a tiny chemical factory, performing many millions of ... molecules alone), and it then uses this energy to generate order within itself. ...... has no effect on the electron-transfer properties of NADPH compared with NADH, but ...