Question

Section 14.2 

5) Dietary glycogen: 

a. is broken down to glucose by a different group of enzymes than is dietary starch. 

b. is broken down to glucose-6-phosphate, which is then absorbed by the intestinal cells. 

c. results in the formation of limit dextrins in the intestine as an intermediate in its digestion. 

d. effectively produces an extra ATP when its glucose goes through glycolysis. 

Section: 14.2 Feeder Pathways for Glycolysis 

6) Fructose: 

a. is broken down by a pathway known as fructolysis. 

b. can be phosphorylated by either hexokinase or fructokinase. 

c. can only be metabolized by liver. 

d. is metabolized in exactly the same way that glucose is. 

Section: 14.2 Feeder Pathways for Glycolysis 

7) Which statement is FALSE? 

a. Galactosemias results from defective or absent lactase in the intestine. 

b. Galactose metabolism requires a nucleotide. 

c. Mannose is phosphorylated by hexokinase. 

d. The overall strategy for metabolizing the common monosaccharides is to convert them into glycolytic intermediates. 

Section: 14.2 Feeder Pathways for Glycolysis Section 

14.3 

8) Fermentation is needed for anaerobic glycolysis: 

a. to convert lactate to pyruvate. 

b. only in anaerobic organisms. 

c. in order to convert NADH back to NAD so glycolysis can continue. 

d. only in organisms that produce ethanol.

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Answer 1

5.d) Dietary glycogen effectively produces an extra ATP, when its glucose goes through glycolysis.

Dietary glycogen is broken down by glycogen phosphorylase to produce glucose-1-phosphate, which then converts to glucose-6-phosphate. Glucose-6-phosphate finally goes through glycolysis to serve as fuel.

6.a) Fructose is broken down by a pathway, known as fluctolysis.

7.a) Galactosemia results from defective or absent lactase in intestine - this statement is false.

Actually, galactosemia results when galactose-1-phosphate uridyltransferase becomes missing or defective.

8.c) Fermentation is needed for anaerobic glycolysis, in order to convert NADH back to NAD⁺, so that glycolysis can continue.