What Are the Reactants of Respiration?

In respiration, organic molecules are oxidized into simpler molecules, usually carbon dioxide and water. The resulting energy is used to fuel many energy requiring processes within the organism.

Nutrients

• Common nutrients used by plants and animals cells include glucose, fatty acids, amino acids and a common oxidizing agent called an electron acceptor (i.e., molecular oxygen).

Oxygen

• Oxygen plays an important function in aerobic cell respiration. Without oxygen, pyruvate (a salt or ester of pyruvic acid) is not metabolized by the cell during respiration, but undergoes a separate process known as fermentation.

Pyruvate

• Anaerobic respiration does not require oxygen when glucose is broken down into pyruvate (a salt or ester of pyruvic acid), but it cannot be further broken down because no oxygen is available. Pyruvate is converted into a waste product.

Carbohydrates

• Cellular respiration is a catabolic process, meaning the breaking down of complex materials (such as carbohydrates) into simpler ones, i.e., sugar molecules and the release of energy.

Foods

• Cellular respiration means the production of energy from different foods consumed by organisms.