Ap Bio
...through the process of respiration.
2. Respiration means breathing–inhaling and exhaling–and it is closely related to getting energy (Figure 9.1).
3. Between 1755 and 1780, Joseph Black, Joseph Priestley, and Jan Ingenhousz experimented with animals and plants in an effort to better understand the process of respiration. They were working without the benefit of modern chemistry and therefore all of their findings are based on a nonexistent substance called "phlogiston" (Figure 9.2).
4. The observations of Priestley and Ingenhousz suggested a natural cycle of reactions in which plants and animals conduct opposite processes.
5. Antoine Lavoisier established that the gas he named oxygen is removed from the air during respiration or combustion and replaced by carbon dioxide.
6. De Saussure concluded that plants incorporate CO2 as they grow and they grow by consuming CO2 and producing oxygen at the same rate.
7. Lavoisier and Pierre de Laplace studied combustion and respiration quantitatively by using a chamber surrounded by ice as a calorimeter. The heat produced in the chamber by burning material or by the respiration of an animal is proportional to the amount of ice melted during the process (Figure 9.3).
8. The biosphere operates on a carbon cycle consisting largely of respiration and photosynthesis (Figure 9.4).
9. Autrotrophs, mostly photoautotrophs such as plants, synthesize organic compounds from CO2 as they grow.
10. Heterotrophs, mostly chemoheterotrophs such as animals, oxidize those compounds back to CO2.
11. Cellular respiration is a chemical process in which energy-rich materials are oxidized to release their energy.
12. In cellular respiration the hydrogen atoms of C6H12O6 are removed (and some oxygen is added), leaving CO2.
13. In respiration, sugar is oxidized to CO2 and water, whereas in photosynthesis essentially the opposite process...
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