Portage Learning BIOD 171 Module 2

Portage Learning BIOD 171 Module 2 EXAM MODULE 2 1. True or False: As movement requires energy, metabolism can be defined as a controlled set of biochemical reactions that occur in only motile organisms in order to maintain life. False. Metabolism occurs in all living organisms, not just those that move. 2. True or False: Enzymes slow down chemical reactions to conserve energy. False. Enzyme catalyze (speed up) chemical reactions. 3. What is a cofactor? And give a general example. A cofactor is a small chemical component that assists an enzyme during the catalysis reactions. A cofactor is usually metal ions. 4. Define anabolism. Anabolism is the process of building up or biosynthesis of macromolecules from small molecular units into much larger complexes. 5. In order to convert proteins into amino acids which metabolic process would be active? Catabolism would be active as proteins are made up of amino acids. Therefore the process described (proteins into amino acids) is the breakdown, or catabolism of protein. 6. Describe the energy transfer process relative to both ATP and ADP ATP has the energy (phosphate group) to donate while ADP can accept energy in the form of a phosphate group. Thus, ATP can be reduced (ATP →ADP + Pi) while ADP can be built into ATP (ADP + Pi →ATP). 7. An organism that derives its energy (generates ATP) from photons of light is called a ? Phototrophic microorganism. 8. An organism that derives its energy by removing electrons from elemental sulfur would be classified as a? Lithotroph 9. A reactive intermediate would be present in which phosphorylation process? A. Photophosphorylation B. Substrate-level phosphorylation C. Oxidative phosphorylation B. The chemical compound losing the phosphate group is referred to as the phosphorylated reactive intermediate. 10. The catabolism of a single molecule of glucose goes through what 3 distinct transitions? The breakdown of glucose goes through (1) Glycolysis then (2) Fermentation or Respiration and finally through (3) the electron transport chain (ETC). 11. What is the most energetic transition in the catabolism of glucose? The electron transport chain yields 34 ATP while both glycolysis and fermentation (or respiration) each yield only 2 ATP. 12. Identify the reactants of the following chemical equation: Glucose + 2NAD+ → 2 NADH + 2 Pyruvate + 2 ATP The reactants are to the left of the arrow: Glucose and 2NAD+ 13. The presence of what molecule ‘signals’ to the cell that glycolysis is about to start? Glucose-6-phosphate (G6P) 14. True or False: In the absence of oxygen fermentation produces 2 ATP. False. Fermentation only reduces NADH back to NAD+ 15. What is the primary byproduct of the TCA cycle? Select all that apply. A. NAD+ B. FAD C. NADH D. FADH2 C and D. The TCA cycle produces an abundance of reduced electron carriers (NADH and FADH2). 16. True or False. The reactants of the TCA cycle directly enter and fuel the electron transport system. False. The products of the TCA cycle (reduced electron carriers) enter and drive the production of ATP via the electron transport system 17. In the absence of glucose, which of the following can be used as alternative energy sources? Select all that apply. A. Lactose B. Nucleic acids C. Carbohydrates D. Lipids A, C, D can all be used as alternative energy sources. 18. For the catabolism of proteins and lipids, which of the following enzymes are used? Select all that apply. A. Ligases B. Proteases C. Transferases D. Lipases B and D. Proteases breakdown proteins while lipases breakdown lipids. 19. True or False. The β-oxidation pathway catabolizes the fatty acid chains of lipids. True 20. True or False. Plants, algae and bacteria all contain chloroplasts. False. Chloroplasts are specific to algae and plants only. 21. The process of carbon fixation begins with which of the following reactants: select all that apply. A. ATP B. Glyceraldehyde-3-phosphate C. CO2 D. NADPH E. H2O A, C, D, and E. Carbon fixation uses the ATP/NADPH produced during light reactions to convert CO2 and H2O into useful sources of energy (carbohydrates). 22. What is one of the main functions of light reactions? Similar to the electron transport chain, one of its main functions is to generate a proton concentration gradient to generate ATP. 23. True or False: Dark reactions can occur in the presence or absence of light. True. The term ‘dark reactions’ (also known as the Calvin Cycle) simply denotes the second stage in photosynthesis—dark reactions do not actually require darkness in order to occur. 24. How many turns (or repititions) of the Calvin Cycle are required to generate one molecule of glucose? Six. 25. Complete the following equation by placing the appropriate numbers where indicated. CO2 + ATP + NADPH + H20 → C6H12O6 + ADP + NADP+ 6 CO2 + 18 ATP + 12 NADPH + 12 H20 → C6H12O6 + 18 ADP + 12 NADP+ 26. Match the following reactions to its corresponding enzyme: 1. A + B → A-B 2. A-B → A + B 3. A- + B →A + B4. Ab + C → A + Cb A- Lyases B- Transferases C- Oxioreductaces D- Hydrolases E- Ligases F- Isomerases 1E 1. A + B → A-B Ligases 2A 2. A-B → A + B Lyases 3C 3. A— + B → A + B— Oxioreductaces 4B 4. Ab + C → A + Cb Transferases