In humans, glycogen is a more useful food-storage molecule than fat because _____________________
(a) a gram of glycogen produces more energy than a gram of fat.
(b) it can be utilized to produce ATP under anaerobic conditions, whereas fat cannot.
(c) it binds water and is therefore useful in keeping the body hydrated.
(d) for the same amount of energy storage, glycogen occupies less space in a cell than does fat.
Choice (b) is the answer. The breakdown of glycogen to glucose does not require oxygen; the glucose can then enter glycolysis and generate ATP by a fermentation process that produces lactic acid. In contrast, fats are broken down to acetyl CoA; this must enter the citric acid cycle, which requires oxygen to keep turning. Choice (a) is incorrect, because 1 g of glycogen (wet or dry) produces less energy than 1 g of fat. Choice (c) is incorrect, because the water bound by glycogen is not useful in keeping the body hydrated and merely contributes to making the glycogen weigh a lot. Choice (d) is incorrect, because the actual mass of glycogen required to store the same amount of energy is sixfold greater than the amount of fat.
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Fill in the blank with the appropriate word.
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A. family and genus. B. first name and last name. C. genus and species. D. domain. E. genus and species AND domain.
________ solutions are those that have a higher concentration of OH- (hydroxyl ions) than H+ ions
Fill in the blank(s) with correct word
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