Cellular respiration chemically breaks down food to produce ATP. Organisms have different gas exchange systems adapted to their environment, such as lungs, gills, or tracheae. Respiration is regulated by control centers in the brain and involves the diffusion of oxygen and carbon dioxide between the lungs and blood via respiratory pigments like hemoglobin. Respiratory disorders can be environmental or congenital but can be prevented through diet and lifestyle changes.

4. Cellular Respiration - Transformation of chemical energy into ATP - Overall Reaction: C 6 H 12 O 6 +6O 2 -> 6CO 2 +6H 2 O + 36 ATP

5. NADH and FADH 2 are e- donors that enable the formation of ATP

15. Mammalian respiration

18. Avian breathing Air sacs act as bellows to keep air flowing through the lungs.

19. Control centers in the brain regulate breathing

20. Gases diffuse down pressure gradients concentration and pressure drives the movement of gases into and out of blood