Oxidation reactions in biological systems generally involve:

a. addition of electrons and hydrogen ions.
b. loss of electrons and addition of hydrogen ions.
c. loss of electrons and either addition or loss of hydrogen ions.
d. addition of electrons and loss of hydrogen ions.
e. loss of electrons and hydrogen ions.

Loss of electrons and hydrogen ions are generally involved in oxidation reactions in biological systems

Explanation:

The substrates involved in the oxidation reaction in biological systems often loss hydrogen ion detached from itself and thereafter an electron is removed. The substrates are then oxidized by the addition of oxygen to the substrates.

These processes are catalyzed by Oxidoreductases and oxidation takes place alongside with reduction.

both anaerobic and aerobic respiration use glucose (or other carbohydrates), proteins and lipids to produce atp and nadh. cell uses those energy molecules, obtained from food and   breaks them down during the chemical reactions of respiration. in anaerobic respiration, nadh is regenerated to nad+ by enzymes lactate dehydrogenase (lactate is produced, e.g. in muscle cells) or by alcohol dehydrogenase where ethanol is produced (alcohol fermentation), while in aerobic respiration, electrons from nadh are deposited in the mitochondria to regenerate nad+ (electron transport chain. anaerobic respiration produces 2 atp per molecule of glucose compared to aerobic respiration where about 38 atp molecules are produced.