14: Metabolic Cycles
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Metabolic pathways linked series of chemical reactions occurring within a cell. The reactants, products, and intermediates of an enzymatic reaction are known as metabolites, which are modified by a sequence of chemical reactions catalyzed by enzymes. In a metabolic pathway, the product of one enzyme acts as the substrate for the next. These enzymes often require dietary minerals, vitamins, and other cofactors to function. There are two types of metabolic pathways that are characterized by their ability to either synthesize molecules with the utilization of energy (anabolic pathway) or break down of complex molecules by releasing energy in the process (catabolic pathway). The two pathways complement each other in that the energy released from one is used up by the other.
- 14.1: Glycolysis
- Glucose is sliced right in half from a 6-carbon molecule to two 3-carbon molecules. This is the first step and an extremely important part of cellular respiration. It happens all the time, both with and without oxygen. And in the process, transfers some energy to ATP.
- 14.3: Lactic Acid Fermentation
- Short spurts of sprinting are sustained by fermentation in muscle cells. This produces just enough ATP to allow these short bursts of increased activity.
- 14.4: The Electron Transport Chain
- At the end of the Krebs Cycle, energy from the chemical bonds of glucose is stored in diverse energy carrier molecules: four ATPs, but also two FADH 2 and ten NADH molecules. The primary task of the last stage of cellular respiration, the electron transport chain, is to transfer energy from the electron carriers to even more ATP molecules, the "batteries" which power work within the cell.
- 14.5: Metabolic Cycles (Exercises)
- These are homework exercises to accompany Chapter 15 of the University of Kentucky's LibreText for CHE 103 - Chemistry for Allied Health. Solutions are available below the questions.
- 14.6: Homeostasis
- The process in which organ systems work to maintain a stable internal environment is called homeostasis. Keeping a stable internal environment requires constant adjustments.