Library · Cellular process
Cellular respiration
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Cellular respiration is how the cell gets energy from glucose. Although it is called respiration, this is not about the lungs but about what happens inside the cell.
The first step is glycolysis: glucose is split into two molecules called pyruvate. If oxygen is present, those pyruvates enter the mitochondrion, a compartment inside the cell. That is where the real work happens: oxidative phosphorylation. A series of components, the electron transport chain, receives the electrons carried by NADH and FADH2, two molecules that pick them up in steps such as glycolysis, and passes them along until it hands them to oxygen. At the same time, it pumps protons to one side, like water building up behind a dam.
When those protons flow back, they spin part of ATP synthase, the enzyme whose name says what it makes: ATP, the form in which the energy extracted from glucose is stored. That part turns like the dam's turbine. The result is roughly 30 to 32 molecules of ATP, whereas glycolysis alone yields 2.
In brief
Cellular respiration extracts energy from glucose as ATP: its first step, glycolysis, splits glucose into two pyruvates, which enter the mitochondrion if oxygen is present.
In oxidative phosphorylation, the electron transport chain carries electrons from NADH and FADH2, loaded in steps such as glycolysis, to oxygen, and pumps protons whose return spins part of ATP synthase.
Part of ATP synthase spins like a turbine.
This yields roughly 30 to 32 ATP; glycolysis alone yields 2.
Sources (2)
- National Center for Biotechnology Information, StatPearls PublishingBiochemistry, Glycolysis, StatPearlsPublished
- National Center for Biotechnology Information, StatPearls PublishingBiochemistry, Oxidative Phosphorylation, StatPearlsPublished
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