Cellular Respiration Explained with Simple Animations

Cellular respiration begins in the cytoplasm with a process called glycolysis.The process starts with a single glucose molecule in the cytoplasm.Initially, glycolysis requires an investment of energy in the form of two ATP molecules.Through a series of ten chemical reactions, the glucose molecule is split into two three-carbon compounds.During this process, electrons are transferred to NAD+ molecules, forming NADH.By the end of glycolysis, the process actually produces four ATP molecules, resulting in a net gain of two ATP, since we invested two ATP at the start.Finally, the three-carbon compounds are converted into pyruvate molecules, which will continue into the next stage of cellular respiration.These pyruvate molecules will move into the mitochondria for further breakdown in the next stage of cellular respiration.The electron transport chain is located in the inner mitochondrial membrane.Electron carriers NADH and FADH2 deliver high-energy electrons to the chain.As electrons move through the complexes, their energy is used to pump protons across the membrane.This creates a proton gradient across the membrane, with more protons accumulating in the intermembrane space.As protons flow back through ATP synthase, their energy is used to produce ATP from ADP and phosphate.At the end of the chain, oxygen accepts the electrons and combines with protons to form water.This process of oxidative phosphorylation is highly efficient, producing approximately thirty-four ATP molecules for each glucose molecule that entered glycolysis.