Deck 4: Bioenergetics

Question 1

By definition, an endergonic reaction is

A) a chemical reaction that requires energy to be added to the reactants before the reaction will take place.
B) a chemical reaction that gives off energy.
C) an enzyme-catalyzed reaction.
D) a chemical reaction that results in products containing less free energy than the original reactants.

Answer 1

A

Question 2

The simplest and most rapid method of producing ATP during exercise is through

A) glycolysis.
B) ATP-CP system.
C) aerobic metabolism.
D) glycogenolysis.

Answer 2

B

Question 3

The total ATP production via aerobic breakdown of glucose is

A) 32 ATP.
B) 36 ATP.
C) 38 ATP.
D) 39 ATP.

Answer 3

A

Question 4

Aerobic production of ATP occurs in the

A) mitochondria in a process called glycolysis.
B) mitochondria (i.e., electron transport chain) in a process called oxidative phosphorylation.
C) mitochondria in a process called beta oxidation.
D) cytoplasm.

Question 5

The calculated efficiency for aerobic respiration is approximately

A) 0%.
B) 34%.
C) 100%.
D) 66%.

Question 6

Fats that are stored in muscle and adipose tissue that play an important role as an energy substrate are

A) phospholipids.
B) cholesterol.
C) triglycerides.
D) lipoproteins.

Question 7

Stored polysaccharides in muscle and other tissues in animals are called

A) glucose.
B) fructose.
C) glycogen.
D) cellulose.

Question 8

The two most important hydrogen (electron) carriers in bioenergetic chemical reactions are

A) NAD and ATP.
B) FAD and ATP.
C) NAD and FAD.
D) NAD and LDH.

Question 9

Enzymes are catalysts that increase the rate of reactions by

A) pulling two substrates together.
B) lowering the energy of activation.
C) binding to a substrate and producing energy.
D) binding to a substrate and releasing protons.

Question 10

If muscle glycogen is the initial substrate, ____________ ATP can be produced via glycolysis.

A) 2.
B) 3.
C) 32.
D) 33.

Question 11

Which of the following definitions describes the function of the "hydrolase" category of enzymes?

A) enzymes that catalyze reactions that result in the rearrangement of the structure of molecules
B) enzymes that catalyze reactions in which groups of elements are removed to form a double bond or are added to an existing double bond
C) enzymes that catalyze reactions in which the cleavage of bonds is accomplished by adding water
D) enzymes that catalyze the transfer of elements from one molecule to another

Question 12

The breakdown of creatine phosphate is regulated by

A) the amount of lactate dehydrogenase in the muscle.
B) the amount of NAD in the sarcoplasm of the muscle.
C) ADP concentration in the cytoplasm.
D) the pH of the interstitial fluid.

Question 13

The most important high-energy phosphate compound in the muscle cell is

A) NAD.
B) FAD.
C) ATP.
D) GTP.

Question 14

Coupled reactions are defined as

A) reactions that are linked together via the same enzyme.
B) reactions that are linked together, with the liberation of free energy in one reaction being used to drive the second reaction.
C) reactions that are not directly linked together but are related to the same enzyme.
D) reactions that are linked via common substrates.

Question 15

Each pair of electrons passed through the electron transport chain from NADH to oxygen releases enough energy to form

A) 1.5 ATP.
B) 2.5 ATP.
C) 5.0 ATP.
D) 10.0 ATP.

Question 16

The primary function of the Krebs cycle is to

A) complete the oxidation of carbohydrates, fats, and proteins (i.e., form NADH and FADH).
B) produce ATP via substrate-level phosphorylation.
C) prime glycolysis for the production of ATP.
D) produce H₂O and ATP.

Question 17

Which of the following statements about glycolysis is correct?

A) glycolysis occurs in the mitochondrial matrix.
B) glycolysis ends with the production of pyruvic acid or lactic acid.
C) glycolysis can start with glucose of fatty acids.
D) glycolysis doesn't produce any ATP.

Question 18

The most important rate limiting enzyme in glycolysis is

A) lactate dehydrogenase.
B) hexokinase.
C) phosphofructokinase.
D) pyruvate kinase.

Question 19

The first law of thermodynamics states that energy

A) cannot be created nor destroyed.
B) cannot be stored.
C) cannot be converted into other forms.
D) transformations result in an increase in entropy.

Question 20

Elevated blood levels of lactate dehydrogenase may assist in the diagnosis of which medical condition?

A) Paget's disease
B) pancreatitis
C) muscular dystrophy
D) myocardial infarction

Question 21

The caloric (kcal) yield of one gram of protein is

A) 4 kcal/g.
B) 7 kcal/g.
C) 9 kcal/g.
D) the same as that of one gram of fat.

Question 22

In general, the higher the intensity of the activity, the greater the contribution of

A) aerobic energy production.
B) anaerobic energy production.
C) the Krebs cycle to the production of ATP.
D) the electron transport chain to the production of ATP.

Question 23

The enzyme responsible for catalyzing the immediate energy system is

A) adenylate cyclase.
B) myosin ATPase.
C) creatine kinase.
D) lactate dehydrogenase.

Question 24

The accumulation of _________ would slow glycolysis by inhibiting its rate limiting enzyme.

A) ADP
B) ATP
C) P_i
D) none of these

Question 25

The rate limiting enzyme in the Krebs cycle is

A) isocitrate dehydrogenase.
B) hexokinase.
C) succinate dehydrogenase.
D) cytochrome oxidase.

Question 26

The shorter the activity, the ____________ the contribution of anaerobic energy sources.

A) greater
B) lesser

Question 27

In order to be oxidized for the eventual formation of ATP, amino acids must first be broken down into proteins.

Question 28

The process of beta-oxidation involves

A) breaking down stored triglycerides to FFA.
B) the addition of oxygen to a fatty acid.
C) the breakdown of a fatty acid to acetyl-CoA.
D) none of these.

Question 29

The actual ATP yield from aerobic metabolism of one molecule of glucose is different from the theoretical yield because

A) the net production of ATP is higher than previously thought.
B) it accounts for the fact that an additional H⁺ is required to move ATP into the cytoplasm.
C) it eliminates the ATP derived from NADH and FADH₂.
D) of all of these.

Question 30

Body temperature increases slightly during exercise. This would have the effect of

A) increasing enzyme activity.
B) decreasing enzyme activity.
C) denaturing enzymes.
D) none of these.

Question 31

The primary purpose of the Krebs cycle is to

A) complete the oxidation of foodstuffs using NAD and FAD as hydrogen (electron) carriers.
B) catalyze the phosphorylation of ADP from creatine phosphate.
C) oxidize foodstuffs and transfer those electrons to pyruvic acid.
D) consume lactate.

Question 32

A rate-limiting enzyme in the aerobic synthesis of ATP in the mitochondria is

A) phosphofructokinase.
B) isocitrate dehydrogenase.
C) myosin ATPase.
D) ATP synthase.

Question 33

Once pyruvic acid has been converted to lactic acid, it cannot be turned back into pyruvic acid.

Question 34

The enzyme-substrate complex is

A) best described by the lock and key model.
B) not influenced by pH.
C) a terminal point for both the enzyme and substrate (neither can be reused).
D) more likely to occur in a 20 degrees C environment than a 40 degrees C one.

Question 35

The conversion of pyruvate to lactate requires

A) the enzyme LDH.
B) NADH + H^+.
C) both of these.
D) neither of these.

Question 36

Which of the following is true concerning the electron transport chain?

A) The associated oxidation and reduction reactions provide the energy needed to pump H⁺ ions into the mitochondrial matrix
B) The flow of H⁺ ions from the inter-membrane space back into the mitochondrial matrix powers the (aerobic) production of ADP
C) The electrons passed down the chain will eventually be used to help form water
D) The end result of the electron transport chain is the formation of oxygen