Significance of Respiration

Bringing the chapter's themes together, respiration matters to the organism in several distinct ways:

1. Respiration provides the energy needed for the synthesis of biomolecules.
2. It is also the source of energy for cell division, growth, repair and replacement of worn-out parts, movement and locomotion, and every other energy-demanding activity of the cell.
3. Various intermediates of the Krebs cycle serve as building blocks for synthesising other complex compounds - a direct expression of the cycle's amphibolic character (see 13.3.2).
4. Coupled with photosynthesis, respiration helps maintain the balance of CO₂ and O₂ in the atmosphere. The two processes are, in fact, to a large extent the reverse of one another: photosynthesis reduces CO₂ to glucose, using light energy, while respiration oxidises that glucose back to CO₂ and water, releasing the trapped energy again. …