Editing Metabolic pathway (section)

===Catabolic pathway (catabolism)===
A '''[[catabolic pathway]]''' is a series of reactions that bring about a net release of energy in the form of a high energy phosphate bond formed with the energy carriers adenosine diphosphate (ADP) and guanosine diphosphate (GDP) to produce adenosine triphosphate (ATP) and guanosine triphosphate (GTP), respectively.<ref name="Harvey"/>{{rp|91–93}} The net reaction is, therefore, thermodynamically favorable, for it results in a lower free energy for the final products.<ref name="Clarke">{{cite book| vauthors = Berg JM, Tymoczko JL, Stryer L |title=Biochemistry|date=2002|publisher=W. H. Freeman|location=New York, NY |isbn=978-0-7167-3051-4 |edition=5th |url=https://archive.org/details/biochemistrychap00jere}}</ref>{{rp|578–579}} A catabolic pathway is an exergonic system that produces chemical energy in the form of ATP, GTP, NADH, NADPH, FADH2, etc. from energy containing sources such as carbohydrates, fats, and proteins. The end products are often carbon dioxide, water, and ammonia. Coupled with an endergonic reaction of anabolism, the cell can synthesize new macromolecules using the original precursors of the anabolic pathway.<ref>{{cite book| vauthors = Raven PH, Evert RF, Eichhorn SE |title=Biology of plants|date=2011|publisher=Freeman|location=New York, NY|isbn=978-1-4292-1961-7|pages=100–106|edition=8th }}</ref> An example of a coupled reaction is the phosphorylation of [[Fructose 6-phosphate|fructose-6-phosphate]] to form the intermediate [[Fructose 1,6-bisphosphate|fructose-1,6-bisphosphate]] by the enzyme [[phosphofructokinase]] accompanied by the hydrolysis of ATP in the pathway of [[glycolysis]]. The resulting chemical reaction within the metabolic pathway is highly thermodynamically favorable and, as a result, irreversible in the cell.

<chem>Fructose-6-Phosphate + ATP -> Fructose-1,6-Bisphosphate + ADP</chem>

====Cellular respiration====
{{Main|Cellular respiration}}

A core set of energy-producing [[catabolic]] pathways occur within all living organisms in some form. These pathways transfer the energy released by breakdown of [[nutrient]]s into [[Adenosine triphosphate|ATP]] and other small molecules used for energy (e.g. [[Guanosine triphosphate|GTP]], [[NADPH]], [[FADH2|FADH<sub>2</sub>]]). All cells can perform [[anaerobic respiration]] by [[glycolysis]]. Additionally, most organisms can perform more efficient [[aerobic respiration]] through the [[citric acid cycle]] and [[oxidative phosphorylation]]. Additionally [[plant]]s, [[algae]] and [[cyanobacteria]] are able to use sunlight to [[anabolic]]ally synthesize compounds from non-living matter by [[photosynthesis]].
[[File:Gluconeogenese Schema 2.png|thumb|Gluconeogenesis mechanism|557x557px]]