Q4 / 200 · MHT CET - Medical 2026 (22 April Shift 1) · Biology
The protons released during the oxidation of NADH+H$^+$ and FADH$_2$ in mitochondria follow the paths given below EXCEPT:
- AProtons are released into intermembrane space.
- BThey are channelized into the inner chamber by $\text{F}_0$ part of oxysome present in the inner membrane.
- CThese protons react with reduced molecular oxygen to form water molecule.
- Correct answerDThis water molecule evaporates through the stomata.
Solution
During the electron transport chain in mitochondria, the oxidation of NADH+H$^+$ and FADH$_2$ releases protons and electrons.
The protons are pumped from the mitochondrial matrix into the intermembrane space, creating a proton gradient.
These protons then move back into the inner chamber (matrix) through the F$_0$ channel of the ATP synthase (oxysome) present in the inner mitochondrial membrane, driving ATP synthesis.
In the matrix, the protons combine with the terminal electron acceptor, molecular oxygen, and electrons to form metabolic water.
The metabolic water formed is generally utilized within the cell for various biochemical processes and does not specifically evaporate through the stomata as its primary fate. Therefore, the statement about the water molecule evaporating through the stomata is the exception.
Answer: This water molecule evaporates through the stomata.
The protons are pumped from the mitochondrial matrix into the intermembrane space, creating a proton gradient.
These protons then move back into the inner chamber (matrix) through the F$_0$ channel of the ATP synthase (oxysome) present in the inner mitochondrial membrane, driving ATP synthesis.
In the matrix, the protons combine with the terminal electron acceptor, molecular oxygen, and electrons to form metabolic water.
The metabolic water formed is generally utilized within the cell for various biochemical processes and does not specifically evaporate through the stomata as its primary fate. Therefore, the statement about the water molecule evaporating through the stomata is the exception.
Answer: This water molecule evaporates through the stomata.
Hence, the correct answer is option: 'D'.