1. Patients with mitochondrial disorders share many symptoms, such as muscle weakness, because mitochondria ________. 1.organize the construction of muscle protein 2.generate the ATP that is necessary for muscle contraction 3.store and then release the oxygen used during muscle contraction 4.facilitate the transport of glucose across the muscle cell membrane 12345

2. Regardless of the source of energy, virtually all living organisms convert their energy into ________ before using it. 1.glucose 2.carbon dioxide 3.ATP 4.light and heat 12345

3. The oldest energy-releasing metabolic pathways ________. 1.were operating billions of years ago 2.were anaerobic; free oxygen was not used in the process 3.are still used today by prokaryotes and protists that live in places were oxygen is unavailable 4.all of the choices 12345

4. Rank the steps in aerobic respiration, from greatest to least, by how much ATP is produced. 1.Krebs cycle, glycolysis, electron transfer phosphorylation 2.electron transfer phosphorylation, Krebs cycle, glycolysis 3.glycolysis, Krebs cycle, electron transfer phosphorylation 4.electron transfer phosphorylation, glycolysis, Krebs cycle 12345

5. What statement best characterizes glycolysis? 1.glycogen, a large carbohydrate molecule, is broken down to monosaccharides 2.a molecule of glucose is converted into two molecules of pyruvate 3.there is a net energy cost to the cell when activating glucose, but the remaining steps in aerobic respiration recover this cost 4.the carbon atoms in glucose are oxidized to form carbon dioxide and water 12345

6. Substrate-level phosphorylation, in contrast to electron transfer phosphorylation, can occur ________. 1.both in the cytoplasm and the mitochondrion 2.under anaerobic conditions 3.without the aid of the enzyme ATP synthase 4.all of the choices are correct 12345

7. After two turns of the Krebs cycle, the original glucose is completely disassembled but the cell has gained only four ATP. What happened to the bulk of the energy? 1.it has been converted to heat and is no longer capable of producing work 2.glucose is a small molecule; four ATP was all the cell could hope to recover 3.it was used to reduce NAD and FAD but will be recovered during electron transfer phosphorylation 4.it is still contained within the carbon-oxygen bonds of carbon dioxide 12345

8. A mitochondrion has a double membrane with the outer compartment between them. Within the outer compartment, ________. 1.hydrogen ions accumulate to form the proton gradient that drives ATP synthase 2.carbon dioxide accumulates and is stored until it can be transported to the lung 3.the matrix containing Krebs cycle enzymes is located 4.the soluble electron transport enzymes are found 12345

9. For glycolysis to continue in eukaryotes, NAD+ must be regenerated. In anaerobic environments, this is accomplished by ________, which produces ________ as the end product(s). 1.fermentation, ethanol or lactic acid 2.phosphorylation, ATP 3.an exchange reaction, FADH 2 and NAD+ 4.hydrogenation, NADPH 2 12345

10. In the absence of oxygen, ________. 1.energy metabolism completely ceases and the organism dies 2.a small amount of ATP can be produced using glycolysis 3.eukaryotic cells can use alternative electron acceptors such as sulfur or iron 4.carbon dioxide molecules can't be constructed and the Krebs cycle stops 12345

11. When glucose availability exceeds energy demands, cells will ________. 1.construct and stockpile ATP indefinitely 2.store glucose as a polysaccharide, usually glycogen 3.produce the hormone glucagon, which causes liver cells to synthesize glycogen 4.ignore the glucose, causing it to leave the body in the urine 12345

12. In humans, the largest amount of energy storage is in ________. 1.fats 2.glycogen 3.glucose 4.starch 12345

13. Which pancreatic hormone stimulates muscles to take in glucose? 1.glucagon 2.insulin 3.estrogen 4.testosterone 12345

14. Which of the following can be broken down and used as an energy source? 1.carbohydrates 2.fats 3.proteins 4.all of the choices 12345

15. What is the final carbon-containing end product of the complete aerobic respiration of glucose? 1.carbon dioxide 2.pyruvate 3.starch 4.water 12345

16. When amino acid availability exceeds the needs of protein synthesis, ________. 1.cells will make storage polypeptides in a way similar to glycogen formation 2.the amino group can be removed and the carbon backbone metabolized for energy 3.some amino acids are converted to urea and eventually eliminated in the urine 4.all of the choices 12345

17. How many ATPs are required for the early stages of glucose breakdown in glycolysis? 1.0 2.1 3.2 4.4 12345

18. Fermentation is associated with a variety of useful products, including ________. 1.alcoholic beverages such as beer and wine 2.dairy products such as cheese, yogurt, and buttermilk 3.cured meats and pickled vegetables 4.all of the choices 12345

19. Fatty acids can be metabolized for energy; they enter aerobic respiration ________. 1.at glycolysis, but first must be converted to glucose 2.at the electron transport step as the reduced electron carriers FADH 2 and NADH 3.in glycolysis after enzymatic conversion to PGAL 4.at the Krebs cycle after cleavage and conversion to acetyl-CoA 12345