Cellular waste product

Cellular waste products are formed as a by-product of cellular respiration, a series of processes and reactions that generate energy for the cell, in the form of ATP. Two examples of cellular respiration creating cellular waste products are aerobic respiration and anaerobic respiration.

Each pathway generates different waste products.

When in the presence of oxygen, cells use aerobic respiration to obtain energy from glucose molecules.

Simplified Theoretical Reaction: C₆H₁₂O_{6 (aq)} + 6O_{2 (g)} → 6CO_{2 (g)} + 6H₂O _(l) + ~ 30ATP

Cells undergoing aerobic respiration produce 6 molecules of carbon dioxide, 6 molecules of water, and up to 30 molecules of ATP (adenosine triphosphate), which is directly used to produce energy, from each molecule of glucose in the presence of surplus oxygen.

In aerobic respiration, oxygen serves as the recipient of electrons from the electron transport chain. Aerobic respiration is thus very efficient because oxygen is a strong oxidant. Aerobic respiration proceeds in a series of steps, which also increases efficiency - since glucose is broken down gradually and ATP is produced as needed, less energy is wasted as heat. This strategy results in the waste products H₂O and CO₂ being formed in different amounts at different phases of respiration. CO₂ is formed in Pyruvate decarboxylation, H₂O is formed in oxidative phosphorylation, and both are formed in the citric acid cycle. The simple nature of the final products also indicates the efficiency of this method of respiration. All of the energy stored in the carbon-carbon bonds of glucose is released, leaving CO₂ and H₂O. Although there is energy stored in the bonds of these molecules, this energy is not easily accessible by the cell. All usable energy is efficiently extracted.

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