Question

Biological oxidation of respiratory substrate causes
a. Gain of oxygen
b. Gain of Hydrogen
c. Loss of oxygen
d. Loss of Hydrogen

Answer 1

The combination of oxidation-reduction transformations substances in living organisms is called biological oxidation. The reaction which takes place with a change in the state of oxidation of atoms is called oxidation-reduction reaction. The organic molecule that breaks down to release energy for the ATP synthesis is called the respiratory substrate.

Complete answer:
The food is biologically oxidized intake by humans with the help of enzymes that are present in the body to release energy in the form of ATP. This overall process is called respiration and respiratory breakdown of various substrates involved in this like carbohydrates, fats, or proteins. It is a process of oxidation and therefore it involves the loss of hydrogen.

The reducing equivalents of $NADH$, $FAD{H_2}$ in this process are produced and are electron-rich. We respire oxygen when electrons donate which releases energy that is used for the biological processes of life.

Oxidation is the gain of oxygen of atoms. In the process of oxidation chemical species increase that are in the oxidation state. The oxygen gas is the first oxidizing agent in the process of oxidation.

The reduction in the gain of hydrogen atoms. In the process of reduction, there is an addition of electrons. The molecule will reduce if you add one or two electrons in the reaction.
In the process of reduction, there is a loss of oxygen. The oxygen is removed in the reaction from another substance by a reducing agent.

Therefore, in the process of biological oxidation, there is a loss of hydrogen atoms.

Hence, the correct answer is option (D).

Note: The biological oxidation is the process that takes place in the electron transport chain. In the respiratory substrate of biological oxidation, the process of respiration occurs that generates ATP which is an inorganic compound. It serves as an electron acceptor. The oxidation of ${O_2}$ and the reduction of ${H_2}O$ take place in the biological oxidation process.