Understanding Cellular Respiration: Pathway, Yields, and Coenzymes

Question 1 NADH is made during – Glycolysis Pyruvate oxidation Krebs cycle All of the above

Question 2 Most of the ATP made by aerobic respiration is made during – Glycolysis Electron transport chain Pyruvate oxidation Krebs cycle Substrate-level phosphorylation (what is the difference between substrate-level and oxidative phosphorylation, anyway?)

Question 3 Glycolysis costs ____ATPs, but makes ___ATPs; thus it has a net yield of ___ATPs. 3, 6, 3 2, 4, 2 2, 2, 0 0, 2, 2 4, 8, 4

Question 4 The 2 carbons in acetyl–CoA can eventually used to help form — Glucose ATP Pyruvate Oxaloacetate Carbon dioxide

Question 5 All of the glycolysis reactions do not require oxygen (aerobic environment) and can take place in an anaerobic (without oxygen) environment. This is true This is false

Question 6 What is the function of the coenzymes, NADH and FADH2 ? Charging electrons to power ATP synthase Catalyzing the formation of acetyl-CoA Providing electrons and H+ to the electron transport chain Transporting CO2 into the mitochondria Acting as a terminal electron acceptor

Question 7 Lactic acid fermentation is an anaerobic process? This is true This is false

Question 8 The theoretical ATP yield is 38 for prokaryotes and 36 for eukaryotes. Why is there a difference? 2 ATPs are used during glycolysis for prokaryotes but not eukaryotes The Krebs cycle only occurs in eukaryotes No FADH2 is produced in prokaryotic respiration NADH made during glycolysis must be transported into the mitochondria of eukaryotes.

Question 9 An experimental drug blocks the decarboxylation reactions that convert pyruvate into acetyl-CoA. A cell treated with this drug would not be able to complete glycolysis. This is true This is false

Question 10 When making wine, grape juice and yeast are sealed into a container. Why must the container be air tight? To prevent the buildup of lactic acid Fermentation only occurs in the absence of oxygen Yeast cannot live in aerobic environments To prevent the yeasts from dying To increase the production of acetyl-CoA

Question 11 What happens to the electron’s energy as it moves through the electron transport chain? The electrons gain energy through each transfer The electrons lose energy through each transfer The energy content is unchanged The energy drops to a different orbital

Question 12 During a heart attack blood flow to the cardiac muscle is restricted. How would this affect cellular respiration? ATP production would be increased ATP production would remain unchanged ATP production would be decreased The cell would switch to alcohol fermentation

Answer Key to MC questions D B B A A C A D B B B C

Study Activities: • Draw out the entire pathway of cellular respiration, starting with glycolysis, going through pyruvate oxidation, moving through the Krebs (Citric Acid) Cycle, ending with the electron transport chain and oxidative phoshorylation. You do not need to memorize each compound at every step, or the enzymes that catalyze every step, but by writing these out, you will gain an appreciation for the amazing biochemistry that is used to harvest energy from glucose. • After the above, write out an ”accounting sheet” that accounts for the production of NADH, FADH2, and ATP in the above pathway. • Explain the difference in theoretical yields of ATP by respiration in bacteria (prokaryotes) vs. eukaryotes [e.g. yeast, humans, fruit flies ]

Understanding Cellular Respiration: Pathway, Yields, and Coenzymes