CHEMIOSMOTIC HYPOTHESIS
*Chemiosmotic hypothesis:
→Chemiosmotic hypothesis proposed by Peter Mitchell in 1961.
→This hypothesis explains, how ATP is generated at the electron transport system (ETS) of mitochondria
and chloroplast.
**Chemiosmotic hypothesis within the mitochondria:
→At the inner membrane of mitochondria; NADH-Q reductase, cytochrome reductase and cytochrome oxidase
pump the protons (H+) from mitochondrial matrix into the intermembrane space.
→This causes to charge, the outer side of inner membrane positively and conversely the inner side negatively.
→Then, the ATP synthase pumps the protons back into the matrix.
→While the protons flow back into the matrix, ATP synthase uses the gradient energy of protons to phosphorylate
ADP, making ATP.
**Chemiosmotic hypothesis within the chloroplast:
→At the thylakoid membrane of chloroplast; the cytochrome pumps the protons (H+) from the stroma into
the thylakoid space.
→At the same time, the splitting of water occurs at the thylakoid space.
→These cause to charge, the inner side of thylakoid membrane positively and conversely the outer side
negatively.
→Then, the ATP synthase pumps the protons back into the stroma.
→While the protons flow back into the stroma, ATP synthase uses the gradient energy of protons to phosphorylate
ADP, making ATP.
