Harvesting Energy: Glycolysis and Cellular Respiration - General Biology | BIOL 1005, Study notes of Biology

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Chapter 8 Harvesting Energy: Glycolysis and Cellular Respiration Vocabulary acetyl Co-A: After each pyruvate is split into CO2 and a two-carbon molecule called an acetyl group , which immediately attaches to coenzyme A and forms acetyl CoA aerobic: using oxygen anaerobic: not using oxygen cellular respiration: the oxygen-requiring reactions, occurring in mitochondria, that break down the end products of glycolysis into carbon dioxide and water while capturing large amounts of energy as ATP electron transport chain: a series of electron carrier molecules, found in the thylakoid membranes of chloroplasts and the inner membrane of mitochondria, that extract energy from electrons and generate ATP or other energetic molecules fermentation: anaerobic reactions that convert the pyruvic acid produced by glycolysis into lactic acid or alcohol and CO glucose activation: when one molecule of glucose undergoes two enzyme-catalyzed reactions, each of which uses ATP energy. glycolysis: reactions, carried out in the cytoplasm, that break down glucose into two molecules of pyruvic acid, producing two ATP molecules, does not require oxygen, but can proceed when oxygen is present Krebs cycle: a cyclic series of reactions, occurring in the matrix of mitochondria, in which the acetyl groups from the pyruvic acids produced by glycolysis are broken down to CO2, accompanied by the formation of ATP and electron carriers, also called citric acid cycle Mitochondrial matrix: the fluid contained w/I the inner membrane of a mitochondrion NADH: formed by two high-energy electrons and a hydrogen ion are transferred to NAD+ forming NADH, it is a high-energy electron carrier Pyruvate: a three-carbon molecule that is formed by glycolysis and then used in fermentation or cellular respiration Things to Know:

1. During complete glucose metabolism, what percent of the energy is captured and stored in ATP? Why isn’t all of the energy in glucose stored in ATP? 40% of the energy is captured and stored in ATP. Over half of the energy produced by glucose breakdown is liberated as heat.
2. What is the first step in glucose breakdown? Where does it take place? List the products of this first step. The first step in glucose breakdown is glycolysis. It takes place in the cytosol, and does not require oxygen. Two ATP molecules and two NADH molecules are formed.
3. If oxygen is absent, what process follows glycolysis? If oxygen is present, what process follows glycolysis? If oxygen is absent fermentation follows glycolysis. If oxygen is present cellular respiration occurs.
4. You should know the products of the 2 types of fermentation and what types of cells will carry out these processes. Two types of fermentation are lactic acid fermentation and alcoholic fermentation. Lactic acid fermentation produces lactate and alcoholic fermentation produces ethanol and CO2. Various microorganism and muscles in people and other animals carry out lactic acid fermentation. Where as other microorganisms such as yeast carryout alcoholic fermentation.
5. Where does cellular respiration take place in eukaryotic cells? Cellular respiration takes place in the mitochondria.
6. You should know the 3 steps in cellular respiration along with the ATP and electron carrier yield from each. The three stages are 1) When the pyruvate enters the mitochondria, acetyl CoA is produced 2) The acetyl CoA then enters a series of enzyme-catalyzed reaction called the Krebs cycle, 1 ATP for every acetyl CoA molecule is produced, and 2 NADH and 1 FADH2 is produced for every acetyl CoA 3)Chemismosis, the ETC uses the energy in the high-energy electrons to generate a gradient of H+. This energy is then harnessed to generate ATP. An additional 32 or 34 ATP molecules for each molecule of glucose is produced.
7. What is the role of oxygen in aerobic cellular respiration? Oxygen acts as the final acceptor of electrons from the electron transport chain, and is therefore required for aerobic cellular respiration.
8. How are fats and proteins metabolized?

Fats are broken down, when the bonds btwn the fatty acids and glycerol are hydrolyzed. The glycerol part of the fat, after activation by ATP, feeds directly into the middle of the glycolysis pathway. The fatty acids are transported into the mitochondria, where enzymes in the inner membrane and matrix chop them into acetyl groups, these groups attach to CoA to form acetyl CoA, which enters the Krebs cycle. Proteins, the amino acids can be used to produce energy. First they are converted to pyruvate, acetyl CoA, or the compounds of the Krebs cycle. These molecules then proceed through the remaining stages of cellular respiration.

9. How is fat synthesized from sugar? The monosaccharides are broken down to pyruvate and converted to acetyl CoA. If ATP is present, acetyl CoA will be used to make fatty acids by a series of reactions that are basically the reverse of fatty acid breakdown. If ATP is needed the acetyl CoA will enter the Krebs cycle.