Chapter 13 Quiz

Although the citric acid cycle itself does not use O2, it requires a functioning electron transport chain (which uses O2) in order to regenerate which molecule for further use in the citric acid cycle?Choose one: A. NAD+ B. ATP C. ADP D. FADH2 E. NADH

A. NAD+

How do enzymes maximize the energy harvested from the oxidation of food molecules? Choose one: A. They allow the stepwise oxidation of food molecules, which releases energy in small amounts. B. They allow what would otherwise be an energetically unfavorable oxidation reaction to occur. C. They guarantee that each reaction involved in the oxidation of food molecules proceeds in just one direction. D. They allow oxidation reactions to take place without an input of activation energy. E. They allow a larger amount of energy to be released from food molecules such as glucose.

A. They allow the stepwise oxidation of food molecules, which releases energy in small amounts.

CO2 is released in which steps of the citric acid cycle? Choose one: A. Steps 1 and 5 B. Steps 3 and 4 C. Steps 2 and 4 D. Steps 1 and 8 E. Steps 2, 3, and 4

B. Steps 3 and 4

When food is plentiful, animals can store glucose as what? Choose one: A. acetyl CoA B. glycogen C. glucose 6-phosphate D. glycogen or starch E. starch

B. glycogen

The ethanol in wine and beer is produced from metabolic reactions carried out by the yeast Saccharomyces cerevisiae. Since it is of great commercial value, researchers have studied factors that influence ethanol production. To maximize ethanol yield, which environmental factor should be limiting? Choose one: A. carbon dioxide B. oxygen C. glucose D. sunlight

B. oxygen

What is the difference between NAD+ and NADH? Choose one: A. NADH is involved in biosynthetic reactions. B. NADH carries an extra phosphate group. C. NADH carries an extra proton and two high-energy electrons. D. NADH is the oxidized form, while NAD+ is the reduced form. E. NADH is an electron acceptor, whereas NAD+ is an electron donor.

C. NADH carries an extra proton and two high-energy electrons.

What occurs in the first step of the citric acid cycle? Choose one: A. NADH is produced. B. CO2 is released. C. Two molecules of acetyl CoA combine to form oxaloacetate. D. A two-carbon molecule is combined with a four-carbon molecule to form citrate. E. ATP is consumed.

D. A two-carbon molecule is combined with a four-carbon molecule to form citrate.

In the electron transport chain, the oxygen atoms in O2 become part of which of the following molecules?Choose one: A. CO2 B. ATP C. glucose (C6H12O6) D. H2O E. NADH

D. H2O

What happens to the energy captured during glycolysis and the citric acid cycle by the activated carriers NADH and FADH2. Choose one: A. It is passed to ADP to form ATP. B. It is passed to an electron transport chain that uses it to oxidize food molecules. C. It is passed to an electron transport chain that uses it to produce oxygen. D. It is passed to an electron transport chain that uses it to generate a proton gradient across the inner mitochondrial membrane. E. It is used to drive biosynthetic reactions.

D. It is passed to an electron transport chain that uses it to generate a proton gradient across the inner mitochondrial membrane.

You are packing for a hiking trip during which you'll be burning a lot of calories with physical activity. You want to pack as efficiently as possible since you need to carry a tent and all your food. You can get the most calories out of 5kg of food if it is in the form of A. glucose B. starch C. glycogen D. fat

D. fat