LAB FIVE CELL RESPIRATION
Aerobic cellular respiration is the release of energy from organic compound from organic compounds by metabolic chemical oxidation in the mitochondria within each cell. Cellular respiration involves a series of enzyme-mediated reactions. The equation below shows the complete oxidation of glucose. Oxygen is required for this energy-releasing process to occur. C6H12O6 + 6O2 -> 6CO2 + 6H2O + 686 kilocalories of energy/mole of glucose oxidized PURPOSE This lab provided process of cellular respiration and how it is affected by temperature in both germinating and dormant pea seeds. Cellular respiration is an ATP-producing catabolic process in which the electron receiver is an inorganic molecule. It is the release of energy from organic compounds by chemical oxidation in the mitochondria within each cell. Carbohydrates, proteins, and fats can all be metabolized, but cellular respiration usually involves glucose: C6H12O6 + 6O2 → 6CO2 + 6H2O + 686 Kcal of energy/mole of glucose oxidized. Cellular respiration involves glycolysis, the Krebs cycle, and the electron transport chain. Glycolysis is a catabolic pathway that occurs in the cytosol and partially oxidizes glucose into two pyruvate (3-C). The Krebs cycle occurs in the mitochondria and breaks down a pyruvate (Acetyl-CoA) into carbon dioxide. These two cycles both produce a small amount of ATP by substrate-level phosphorylation and NADH by transferring electrons from substrate to NAD+. The Krebs cycle also produces FADH2 by transferring electrons to FAD. The electron transport chain is located at the inner membrane of the mitochondria and accepts energized electrons from enzymes that are collected during glycolysis and the Krebs cycle, and couples this exergonic slide of electrons to ATP synthesis or oxidative phosphorylation. This process produces most of the ATP. Cellular respiration can be measured in two ways: the consumption of O2 (how many moles of O2 are consumed in cellular respiration) and production of CO2 (how many moles of CO2 are produced in cellular respiration). PV = nRT is the formula for the inert gas law, where P is the pressure of the gas, V is the volume of the gas, n is the number of molecules of gas, R is the gas constant, and T is the temperature of the gas in degrees K. This law shows several important things about gases. If temperature and pressure are kept constant then the volume of the gas is directly proportional to the number of molecules of the gas. If the temperature and volume remain constant, then the pressure of the gas changes in direct proportion to the number of molecules of gas. If the number of gas molecules and the temperature remain constant, then the pressure is inversely proportional to the volume. If the temperature changes and the number of gas molecules is kept constant, then either pressure or volume or both will change in direct proportion to the temperature. Materials Materials are necessary for the lab: 2 thermometers, 2 shallow baths, tap water, ice, paper towels, masking tape, germinating peas, non-germinating (dry) peas, glass beads, 100 mL graduated cylinder, 6 vials, 6 rubber stoppers, absorbent and non- absorbent cotton, KOH, a 5-mL pipette, silicon glue, paper, pencil, a timer, and 6 washers. Hypothesis The respirometer with only germinating peas will consume the largest amount of oxygen and will convert the largest amount of CO2 into K2CO3 than the respirometers with beads and dry peas and with beads alone. The temperature of the water...
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