What is produced during the metabolism of food substances within cells?

During the metabolism of food substances within cells, several key products are generated, including energy, carbon dioxide, and sometimes oxygen, especially in the context of cellular respiration and photosynthesis.

Energy is primarily produced in the form of ATP (adenosine triphosphate) through processes like glycolysis, the citric acid cycle, and oxidative phosphorylation. This energy is crucial for various cellular functions, such as muscle contraction, active transport, and biosynthesis.

Carbon dioxide is a byproduct of aerobic respiration when glucose is broken down to produce ATP. This occurs in the mitochondria, where pyruvate derived from glucose is further processed, leading to the release of carbon dioxide as a waste product.

In the case of photosynthetic organisms, oxygen is produced as a byproduct during the light-dependent reactions of photosynthesis. This process converts light energy into chemical energy stored in glucose, with oxygen released into the atmosphere.

Thus, the correct answer encompasses the production of energy as well as gases like carbon dioxide and oxygen, recognizing that all of these products can occur as a result of the metabolic processes in different organisms and contexts.