The following statements concern the relationship between mi

The following statements concern the relationship between mitochondrial hydrogen ion concentration and energy storage as ATP during oxidative phosphorylation. Classify each statement as either accurate or inaccurate.

Solution

1. Hydrogen ions cannot freely pass through the inner mitochondrial membrane ( Accurate- as inner mitochondrial membrane is impermeable to almost all small ions and molecules including protons and it requires specific transporter to transport molecules across the inner mitochondrial membrane)

2. Oxidative phosphorylation relies on the proton gradient generated by the ETC (Accurate- as oxidative phosphorylation begins with electrons extracted by oxidation of food,these transfer of electrons down the Electron transport chain leads to pumping of protons.Pumping of proton leads to separation of charge(Matrix is negative and intermembrane space is positive) and difference in concentration of proton across the inner membrane creates a proton gradient.The energy stored in such a gradient is called Proton Motive Force that is utilised for phosphorylation of ADP to generate ATP.

3.ATP synthase uses energy from ATP to move proton into the mitochondrial matrix. (Inaccurate- ATP synthase uses the energy stored in the concentration gradient created due to pumping of proton into the intermembrane space. Because of concentration difference the proton move back from higher concentration in intermembrane space to lower concentration in the matrix and they travel back through ATP synthase machinery generating ATP.

4.Proton concentration is higher in the intermembrane space than in the mitochondrial matrix (Accurate- Energy generated due to flow of electrons through ETC leads to pumping of protons (per pair of electrons, four protons are pumped into the intermembrane space) from matrix to intermembrane space hence concentration of proton in the intermembrane space is higher than the matrix

5. The pH in the intermembrane space is higher than the pH in the mitochondrial matrix (Inaccurate- as the number of proton is higher in the intermembrane space as compared to the matrix the pH of the intermembrane space should be low (more acidic by relation pH is negative log of H⁺ ion concentration) So if H⁺ ion concentration is high in the intermembrane space pH should be low.

6.Energy is generated as a result of difference in H⁺ ion concentration between the intermembrane space and cytoplasm (Inaccurate- energy is generated as a result of difference in H⁺ ion concentartion between the intermembrane space and Matrix not cytoplasm.