2024 MICR 290 MIDTERM EXAM /ACTUAL EXAM WITH CORRECT DETAILED ANSWERS - WEST COAST UNIVERSITY, LATEST UPDATE A+ GRADE

2024 MICR 290 MIDTERM EXAM /ACTUAL EXAM WITH CORRECT DETAILED ANSWERS - WEST COAST UNIVERSITY, LATEST UPDATE 2024 -2025 A+ GRADE 1. Define metabolism, catabolism, and anabolism. What is the role of ATP in catabolism and anabolism? - Metabolism : Chemical process that occurs within a living organism in order to maintain life - Catabolism : The breakdown of complex organic compounds into simpler ones (the energy -releasing processes) - Role of ATP : ATP Synthesis - Anabolism : Building of complex organic molecules from simpler ones (the energy -using processes) - Role of ATP : ATP Hydrolysis 2. What are the components of an enzyme? Describe the general mechanism of enzymatic action. - Enzyme Components : - Apoenzyme (protein portion) - Cofactor (non-protein component), - Coenzymes (Cofactors that are organic molecules) - Holoenzymes are whole active enzymes (apoenzyme and cofactor combined) - Cofactor and substrate bind to apoenzyme to create holoenzyme. 3. Describe factors influence the activity of an enzyme. - Temperature : High temp can denature enzyme - pH : Low pH can denature enzyme Substrate concentration : If there is too much substrate, enzyme activity will decrease due to saturation. 4. Compare and contrast the difference between competitive and noncompetitive inhibitors. Understand feedback (positive) and negative inhibition. - Competitive Inhibitors : Fill the active site of an enzyme and compete with the normal substrate for the active site of an enzyme - Noncompetitive Inhibitors : They interact with another part of the enzymes active site - Positive Inhibition : Release of an initial substance stimulates release or production of other substances, which STIMULATES further release of the initial substance - Negative Inhibition : Release of an initial substance stimulates release or production of other substances that subsequently INHIBITS further release of the initial substance 5. Understand the terms oxidation and reduction. If given a reaction, can you tell which molecule is reduced and which is oxidized? - Oxidation : REMOVAL of one or more electrons from an atom or molecule (reaction that produces energy) - Reduction : It has GAINED one or more electrons 6. What are the three types of phosphorylation reactions that can generate ATP? - Substrate - Level Phosphorylation - ATP is usually generated when a high-energy is directly transferred from a phosphorylated compound to ADP - Oxidative Phosphorylation - Electrons are transferred from organic compounds to one group of electron carriers - The transfer of electrons from one electron carrier to the next releases energy (generate ATP from ADP through a process called chemiosmosis - ATP synthesis using the electron transport chain) - Photophosphorylation - Starts this process by converting light energy to the chemical energy of ATP and NADPH which are used to synthesize organic molecules 7. What are the reactants and end products generated in Glycolysis, Kreb’s Cycle, and ETC? - Glycolysis : Occurs in the CYTOPLASM - Begins catabolism by breaking glucose (6C sugar) into two molecules of pyruvate (2 X 3C molecules) => 2 net ATP are generated - Krebs Cycle : Occurs in the mitochondrial matrix - Degrades pyruvate (3C molecule) to carbon dioxide => 2 more ATP made - ETC (Electron Transport Chain) : Built into the inner mitochondrial membrane - NADH passes its electrons to the proteins of the electron transport chain - Energy carried by these electrons is used to power oxidative phosphorylation which converts ADP to ATP 8. Explain the process of oxidative phosphorylation using an electron transport system. How is ATP generated by chemiosmosis? - Oxidative Phosphorylation : - Electrons are transferred from organic compounds to one group of electron carries THEN the electrons are passed through a series of different electron carrier to molecule of oxygen or other oxidized inorganic / organic molecules - Electron Transport Chain (system) : Sequence of electron carriers used in oxidative phosphorylation - How ATP is generated by chemiosmosis : Transfer if electrons from one elec - tron carrier to the next releasing energy (generate ATP from ADP) 9. Where does each step of carbohydrate metabolism take place in bacteria? How does it differ from eukaryotic cells? - Glycolysis - In anaerobic organisms, (those that do not use oxygen to generate energy), pyruvate may be converted to waste products such as ethanol, lactic acid, acetic acid, and similar molecules. Using oxygen as a terminal electron acceptor, aerobic organisms such as animals and plants completely oxidize pyruvate to form CO2 and H2O in an elaborate stepwise mechanism known as aerobic respiration - Citric Acid Cycle - Converts pyruvate from glycolysis to acetyl - CoA 10. Compare and contrast aerobic respiration, anaerobic respiration, and fermentation. Pay attention to the different terminal electron acceptors used in each process. - Aerobic Respiration : - The final electron acceptor in the electron transport chain is molecular oxygen (O2) - Anaerobic Respiration : - The final electron acceptor in the electron transport chain is NOT O2 - Yields less energy than aerobic respiration and not all electron carriers in the ETC participate in the chain - Different than fermentation because electrons get donated to something other than initial substrate - Fermentation :