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- All organisms need a constant supply of eenergy to fuel the activities of life. You get this energy from food. The energy in your food was first captured by sunlight through photosynthesis. Your body then extracts that energy by the process of cellular respiration.
- - Chemical reactions produce new substances by breaking or forming chemical bonds between atoms.
- ) Exergonic reactions release free energy into their surroundings.
- ) Endergonic reactions absorb free energy from their surroundings.
- Adenosine diphosphate (ADP) and adenosinee triphosphate (ATP) are special nucleotides that store energy. Hydrolyzing ATP to ADP releases free energy. The reverse process stores free energy given off by other processes. This method of storing and releasing energy is called the ATP-ADP Cycle.
-Cellular respiration begins with glycolysiis. A cell gains two pyruvate molecules, two ATP molecules, and two NADH molecules for every glucose molecule being metabolized. When oxygen is present (aerobic respiration), pyruvate and NADH are used to produce large amounts of ATP. When oxygen is absent (anaerobic respiration), pyruvate is converted to lactic acid or ethyl alcohol
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