Biology · Nutrition

The word Chemoautotrophic nutrition means energy produced through chemical reactions taking place. The primary work is on inorganic compounds used to synthesise different organic compounds. The reaction involved in chemotrophic nutrition is: NH₄ + 3O₂ + light -> 2NO₂ + 2H₂O + 4H⁺ + energy

This equation represents photosynthesis in green plants. Photosynthesis is the process plants, algae, and some bacteria use to convert light energy into chemical energy, creating their own food (sugars) and releasing oxygen.

This equation shows photosynthesis in bacteria. Photosynthesis in bacteria is a process of converting light energy into chemical energy that occurs in the cell membrane, using different pigments than plants. Two main types exist: oxygenic (in cyanobacteria), which produce oxygen, and anoxygenic (in purple and green sulfur bacteria), which do not, often using compounds like hydrogen sulfide as a source of electrons instead of water.

Bacteria that synthesise organic compounds by obtaining energy from the oxidation of inorganic substances like iron, hydrogen, nitrogen, and sulphur compounds are called chemosynthetic bacteria. The oxidation of ammonium with the release of energy is shown in option C.

This equation is for a reduction reaction. A reduction reaction is a chemical process where a substance gains electrons, resulting in a decrease in its oxidation state. This gain of electrons can also be described as the addition of hydrogen or an electropositive element, or the removal of oxygen or an electronegative element.

Option E is incorrect because it shows the equation for a reaction of the Calvin cycle in C3 plants (regeneration of RUBP from G3P).