Deck 4: Bioenergetics

Question 1

The rate limiting enzyme in the Krebs cycle is

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

Answer 1

A

Question 2

The metabolic process of converting foodstuffs into a biological usable form of energy is called

A)bioenergetics
B)metabolism
C)glycolysis
D)coupled reactions

Answer 2

A

Question 3

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

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

Answer 3

C

Question 4

Enzymes called kinases are responsible for

A)removing electrons from substrates
B)adding hydrogens to substrates
C)adding phosphate groups (i.e. ,phosphorylation of substrates)
D)enzymes that catalyze the transfer of protons from one molecule to another

Question 5

The rate-limiting enzyme in the electron transport chain is

A)phosphofructokinase.
B)isocitrate dehydrogenase.
C)myosin ATPase.
D)cytochrome oxidase.

Question 6

The calculated efficiency for aerobic respiration is approximately

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

Question 7

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 require the same enzyme.
D)reactions that are linked together because they act upon common substrates.

Question 8

The activity of creatine kinase is increased by a rise in ____ levels in the muscle fiber.

A)NAD.
B)ATP.
C)ADP.
D)lactate.

Question 9

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

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

Question 10

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 that are identical in structure.

Question 11

Aerobic production of ATP occurs in the

A)mitochondria in a process called glycolysis.
B)mitochondria in a process called oxidative phosphorylation.
C)mitochondria in a process called beta oxidation.
D)cytoplasm.

Question 12

If muscle glycogen is the initial substrate,the net production ATP resulting during glycolysis is.

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

Question 13

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 14

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 15

Stored polysaccharides in muscle and other tissues in animals are called

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

Question 16

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 17

The total ATP tally from the aerobic breakdown of glucose is

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

Question 18

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 19

The immediate source of energy for muscular contraction is

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

Question 20

The rate limiting enzyme in glycolysis is

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

Question 21

Which of the following statements about glycolysis is correct?

A)glycolysis occurs in the mitochondrial matrix.
B)glycolysis involves the breakdown of glucose or glycogen into two molecules of pyruvate or lactate
C)glycolysis can start with the breakdown of fatty acids.
D)glycolysis does NOT produce any ATP.

Question 22

The conversion of pyruvate to lactate requires

A)the enzyme lactate dehydrogenase.
B)NADH + H^+.
C)A and B are correct.
D)None of the above answers are correct.

Question 23

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 by substrate level phosphorylation.
D)None of the above answers are correct.

Question 24

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

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

Question 25

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 26

Rate limiting enzymes are often located

A)near the beginning of a metabolic pathway.
B)near the end of a metabolic pathway.
C)outside of the main metabolic pathway.
D)None of the above answers are correct.

Question 27

Three molecules of NADH are produced during one turn of the citric acid cycle.How many total ATP molecules can be produced from these three NADH molecules?

A)1.5 ATP
B)2.5 ATP
C)5.0 ATP
D)7.5 ATP

Question 28

A high level of ________ in the muscle fiber would slow glycolysis by inhibiting its rate limiting enzyme.

A)ADP
B)ATP
C)P_i
D)none of the above answers are correct.

Question 29

Body temperature increases slightly during exercise.A 1-2^O C increase in muscle temperature during exercise would likely

A)increase enzyme activity.
B)decrease enzyme activity.
C)denatures enzymes.
D)none of these answers are correct.

Question 30

The term lactate refers to

A)a potential end-product of glycolysis.
B)the conjugate base of lactic acid.
C)the salt of lactic acid.
D)all of the above answers are correct.

Question 31

In order to be oxidized for the eventual formation of ATP,amino acids must first be converted to Acetyl-CoA or Krebs cycle intermediates.

Question 32

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

A)The primary purpose of the electron transport chain is to complete the oxidation of carbohydrates.
B)The primary purpose of the electron transport chain is to produce acetyl-CoA.
C)The primary purpose of the electron transport chain is to harvest the energy from electrons moving down this pathway to produce ATP and water.
D)The end-result of the electron transport chain is the formation of lactate.

Question 33

Cellular reactions that give off energy are called exergonic reactions.

Question 34

Free radicals are molecules that contain an unpaired electron in their outer orbital.

Question 35

Compared to NADH,FADH produces less ATP because

A)FADH has a lower molecular mass than NADH
B)FADH enters the electron transport chain before NADH
C)the electrons from FADH are donated later in the electron transport chain than those by NADH
D)None of the above answers are correct

Question 36

The actual net 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 the energy provided by NADH and FADH is required not only for ATP production but also to transport ATP across the mitochondrial membrane.
C)it eliminates the ATP derived from NADH.
D)All of these answers are correct.

Question 37

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)convert lactate to pyruvate.

Question 38

The breakdown of glycogen into glucose is called gluconeogenesis.

Question 39

Compounds that contain carbon are called inorganic compounds.
38.The field of molecular biology is concerned with understanding the regulation of proteins.

Question 40

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