Chemiosmotic Hypothesis:
The chemiosmotic hypothesis was put forward by Peter Mitchell in 1961. This hypothesis explains the mechanism of ATP synthesis in mitochondria and chloroplasts.

Key Points:
- Basic Concept: The chemiosmotic hypothesis suggests that ATP synthesis is coupled to the movement of protons across a membrane, creating a proton gradient.
- Proton Pump: In both mitochondria and chloroplasts, protons are pumped across the inner membrane from the matrix to the intermembrane space or thylakoid lumen, respectively, by protein complexes called electron transport chains.
- Proton Gradient: This pumping of protons creates a proton gradient, with a higher concentration of protons on one side of the membrane compared to the other.
- ATP Synthase: ATP synthase is an enzyme complex embedded in the membrane that allows protons to flow back into the matrix or stroma, driving the synthesis of ATP from ADP and inorganic phosphate.
- Energy Conversion: The flow of protons through ATP synthase provides the energy needed to convert ADP and inorganic phosphate into ATP.
- Role in Cellular Respiration and Photosynthesis: The chemiosmotic hypothesis is crucial for the production of ATP in both cellular respiration (in mitochondria) and photosynthesis (in chloroplasts).
- Significance: This hypothesis revolutionized our understanding of how energy is converted and stored in biological systems, providing a unifying principle for ATP synthesis in various organisms.
In conclusion, the chemiosmotic hypothesis proposed by Peter Mitchell has had a profound impact on the field of bioenergetics, elucidating the fundamental mechanism underlying ATP synthesis in mitochondria and chloroplasts.

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