NAS Exam 2 Questions with All Correct Answers

NAS Exam 2 Questions with All Correct Answers why is chemical energy needed by cells? - Answer-to maintain homeostasis Define cell respiration - Answer-the mechanism for harvesting energy from fuel molecules; the oxidation of glucose to produce ATP what is the function of the reduced coenzymes? - Answer-They are used to transfer energy to another compound Describe the function of oxidation-reduction reactions in the synthesis of ATP. - AnswerThe reaction that transports energy to reduced coenzymes for synthesis of ATP How are hydrogen atoms involved the redox reactions? - Answer-When redox reactions take place they usually involve the loss of hydrogen atoms. What happens to the energy stored within the newly formed reduced coenzyme? Why is this referred to as phosphorylation? - Answer-Phosphorylation is the addition of a phosphate group to a molecule. Name the four steps in cell respiration - Answer-1. Glycolysis, 2. Formation of acetyl coenzyme A, 3. Krebs cycle, 4. Electron transport chain Why is glycolysis "anaerobic" while the other three pathways are "aerobic." - AnswerBecause oxygen is not required to generate ATP during glycolysis. Where does glycolysis occur? - Answer-in the cytosol Two ATP molecules are used to split a glucose molecule. ATP is actually gained through glycolysis, however. How much ATP is produced by this process and what is the net gain? - Answer-4 ATP gross, 2 net How many reduced coenzyme molecules are produced by glycolysis? - Answer-2 Two molecules are produced by glycolysis. Identify them. - Answer-Pyruvic acid & NADH + H+ Describe the conditions that result in lactic acid production - Answer-anaerobic, not enough oxygen Where within the cell will further oxidation of pyruvic acid molecules occur - Answer-In the matrix of the mitochondria Describe the two steps that result in the formation of acetyl Co-enzyme A. - Answer-1. A molecule of CO2 is removed from the pyruvic acid through decarboxylation. Pyruvic acid is oxidized. 2. The acetyl group binds with Co-enzyme A to form acetyl CoA. Each glucose molecule results in the production of 6 CO2 molecules as a waste gas. How many CO2 molecules are produced in glycolysis and how many in the Krebs cycle? - Answer-2 - Glycolysis, 4 - Krebs cycle How many ATP are produced during the Krebs cycle? - Answer-2 What happens to the remainder of the energy harvested through the Krebs cycle? - Answer-It is transferred to reduced coenzymes that will go through the ETC and be converted to ATP. What is the primary function of the Krebs cycle? - Answer-The production of reduced co-enzymes. What is the function of the electron transport chain? - Answer-The synthesis of ATP What is a by-production of the ETC reaction - Answer-Water as the H- is released and combined w/ oxygen Define Chemiosmosis - Answer-the process by which ATP is produced as hydrogen ions move down their concentration gradient. What protein enzyme is involved in chemiosmosis? - Answer-ATP Synthase Why is ATP construction an example of an anabolic reaction? - Answer-simpler molecules are built up into more complex molecules to form ATP. Why is breaking down larger and more complex food molecules an example of catabolism - Answer-Catabolism is breaking down larger, more complex molecules in order to harvest energy from them. Identify the two different types of reactions involved in energy transfer. - Answer-1. Oxidation & reductions reactions - produce reduced coenzymes which receive energy from high energy fuel molecules. 2. ATP generation reactions - produce ATP which stores the energy harvested from the reduced coenzymes. Describe an oxidation reaction and explain an example involving this energy transfer process - Answer-Oxidation liberates energy in the form of H atoms from high energy fuel molecules. An example is the conversion of lactic acid into pyruvic acid.