Editing Cellular respiration (section)

===Glycolysis===
[[File:Respiration diagram.png|thumb|Out of the cytoplasm it goes into the Krebs cycle with the acetyl CoA. It then mixes with CO<sub>2</sub> and makes 2 ATP, NADH, and FADH. From there the NADH and FADH go into the NADH reductase, which produces the enzyme. The NADH pulls the enzyme's electrons to send through the electron transport chain. The electron transport chain pulls H<sup>+</sup> ions through the chain. From the electron transport chain, the released hydrogen ions make ADP for an result of 32 ATP. Lastly, ATP leaves through the ATP channel and out of the mitochondria.]]
{{Main|Glycolysis}}
[[Glycolysis]] is a [[metabolic pathway]] that takes place in the [[cytosol]] of cells in all living organisms. Glycolysis can be literally translated as "sugar splitting",<ref>{{Cite book|title=Campbell Biology Ninth Edition|last1=Reece |last2=Urry |last3=Cain |last4=Wasserman |last5=Minorsky |last6=Jackson |first1=Jane |first2=Lisa |first3=Michael |first4=Steven|first5=Peter |first6=Robert|publisher=Pearson Education, Inc.|year=2010|pages=168}}</ref> and occurs regardless of oxygen's presence or absence. The process converts one molecule of [[glucose]] into two molecules of [[pyruvate]] (pyruvic acid), generating energy in the form of two net molecules of [[Adenosine triphosphate|ATP]]. Four molecules of ATP per glucose are actually produced, but two are consumed as part of the [[Glycolysis#Preparatory phase|preparatory phase]]. The initial [[phosphorylation]] of glucose is required to increase the reactivity (decrease its stability) in order for the molecule to be cleaved into two [[pyruvate]] molecules by the enzyme [[aldolase]]. During the [[Glycolysis#Pay-off phase|pay-off phase]] of glycolysis, four [[phosphate]] groups are transferred to four ADP by [[substrate-level phosphorylation]] to make four ATP, and two NADH are also produced during the pay-off phase. The overall reaction can be expressed this way:<ref>{{Citation |last=Chaudhry |first=Raheel |title=Biochemistry, Glycolysis |date=2025 |work=StatPearls |url=https://www.ncbi.nlm.nih.gov/books/NBK482303/ |access-date=2025-01-31 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=29493928 |last2=Varacallo |first2=Matthew A.}}</ref>

:Glucose + 2 NAD<sup>+</sup> + 2 P<sub>i</sub> + 2 ADP → 2 [[pyruvate]] + 2 NADH + 2 ATP + 2 H<sup>+</sup> + 2 H<sub>2</sub>O + energy

Starting with glucose, 1 ATP is used to donate a phosphate to glucose to produce [[glucose 6-phosphate]]. Glycogen can be converted into glucose 6-phosphate as well with the help of [[glycogen phosphorylase]]. During energy metabolism, glucose 6-phosphate becomes [[fructose 6-phosphate]]. An additional ATP is used to phosphorylate fructose 6-phosphate into [[fructose 1,6-bisphosphate]] by the help of [[phosphofructokinase]]. Fructose 1,6-biphosphate then splits into two phosphorylated molecules with three carbon chains which later degrades into pyruvate.<ref name=Mannion/>{{rp|88–90}}