Deck 5: Macronutrient Metabolism

Question 1

Which of the following is not a factor that influences the fuel mixture that powers physical activity?

A) Exercise intensity
B) Duration of exercise
C) Group exercise
D) Nutritional status of individual

Answer 1

Group exercise

Question 2

Intense physical activity continued beyond 90 seconds places a progressively greater demand on the relatively slower __________ energy pathways.

A) aerobic
B) glycolytic
C) ATP-PCr
D) glycogenolytic

Answer 2

aerobic

Question 3

__________ sources supply most of the energy for fast movements or during increased resistance to movement at a given speed.

A) Aerobic
B) Anaerobic
C) Fatty acids
D) Amino acids

Answer 3

Anaerobic

Question 4

Macronutrient energy sources for ATP resynthesis during exercise include all of the following except __________.

A) liver and muscle glycogen
B) triacylglycerols within adipose tissue
C) pancreatic glycogen
D) amino acids within skeletal muscle

Question 5

Carbohydrate availability during exercise helps to regulate __________ and its use for energy.

A) lipid mobilization
B) gluconeogenesis
C) lactate
D) epinephrine

Question 6

Compared with lipid, carbohydrate generates about __________ more energy per unit of oxygen consumed.

A) 2%
B) 6%
C) 10%
D) 50%

Question 7

The action of the enzyme __________ stimulates glycogen breakdown in the liver and active muscles.

A) glycogen phosphorylase
B) glycogen synthase
C) glycogen dehydrogenase
D) pyruvate kinase

Question 8

In the transition from rest to moderate exercise, __________ supplies almost all of the energy.

A) glycogen stored in the liver
B) glycogen stored in active muscle
C) free fatty acid circulating in the blood
D) triacylglycerol stored in adipocytes

Question 9

As muscle glycogen stores diminish, __________ becomes the major supplier of carbohydrate energy.

A) glucose from gluconeogenesis
B) glucose from nonactive muscles
C) blood glucose from the liver
D) glucose generated from fatty acids

Question 10

Endurance athletes commonly refer to the extreme sensation of fatigue due to carbohydrate depletion as __________.

A) being in the zone
B) zoning
C) losing the will
D) hitting the wall

Question 11

Aerobically trained muscle has a(n) __________ capacity for carbohydrate metabolism.

A) drastically reduced
B) improved
C) slightly reduced
D) unaltered

Question 12

During submaximal exercise, the endurance-trained muscle exhibits a(n) __________.

A) increased reliance on muscle glycogen and blood glucose as fuel sources and a greater lipid utilization
B) decreased reliance on muscle glycogen and blood glucose as fuel sources and a reduced lipid utilization
C) decreased reliance on muscle glycogen and blood glucose as fuel sources and a greater lipid utilization
D) increased reliance on muscle glycogen and blood glucose as fuel sources and a reduced lipid utilization

Question 13

During submaximal exercise, women derive __________ proportion of total energy from carbohydrate oxidation than men.

A) a greater
B) a smaller
C) the same
D) a significant

Question 14

Compared with untrained muscle, trained muscle tends __________ glycogen reserves.

A) to conserve
B) to rapidly deplete
C) not to conserve
D) to completely deplete

Question 15

Research reveals __________ gender differences in carbohydrate metabolism in exercise.

A) no
B) negligible
C) significant
D) minor

Question 16

The catecholamine response of women after exercise training tends to be __________ compared with that of men.

A) less blunted
B) more blunted
C) slightly increased
D) drastically increased

Question 17

Lactate accumulation leads to fatigue because this compound:

A) causes capillaries to constrict, which reduces muscle blood flow
B) facilitates fatty acid mobilization and utilization, thus reducing the total energy available to muscle
C) inhibits myoglobin from transporting oxygen into the mitochondria
D) lowers the intramuscular pH, which interferes with enzyme activity and energy metabolism

Question 18

Endurance capacity of individuals fed a high-carbohydrate diet tends to be __________ than individuals fed a high-fat diet.

A) dramatically higher
B) slightly higher
C) slightly lower
D) dramatically lower

Question 19

From the standpoint of energy supply, a low-carbohydrate diet makes __________ to engage in vigorous physical activity.

A) it significantly easier
B) it extremely difficult
C) it slightly easier
D) no difference in the ability

Question 20

Fatty acids from each of the following sources except __________ supply the major energy for light exercise.

A) those released from adipocytes
B) circulating plasma triacylglycerol bound to lipoproteins
C) triacylglycerol within the active muscle itself
D) those associated with cell membranes

Question 21

This hormone does not activate lipase.

A) Insulin
B) Epinephrine
C) Norepinephrine
D) Glucagon

Question 22

The primary fuel during light and moderate exercise is __________.

A) lipid
B) protein
C) lipoprotein
D) carbohydrate

Question 23

__________ and lipid contribute energy equally during moderate-intensity exercise.

A) Protein
B) Carbohydrate
C) Amino acids
D) Catecholamines

Question 24

__________ is the preferred fuel during intense aerobic exercise because it rapidly supplies ATP via oxidative processes.

A) Carbohydrate
B) Lipid
C) Protein
D) Amine groups

Question 25

Forty minutes into intense activity glucose uptake by the active muscle increases between __________ the resting uptake.

A) 1 and 2 times
B) 2 and 3 times
C) 7 and 20 times
D) 25 and 50 times

Question 26

During light exercise, __________ remains the main energy substrate.

A) carbohydrate
B) lipid
C) protein
D) water

Question 27

Severely lowered levels of liver and muscle glycogen during physical activity induce all of the following except __________.

A) hypoglycemia
B) fatigue
C) muscle pain
D) hyperglycemia

Question 28

Lactate in the body:

A) represents a metabolic waste product
B) continually forms
C) inhibits citric acid cycle metabolism if not deaminated
D) forms from the union of six pyruvate molecules

Question 29

Toward the end of prolonged exercise for more than 2 hours, circulating __________ supply (supplies) nearly 80% of the total energy contribution.

A) blood glucose
B) free fatty acids
C) glycerol
D) amino acids

Question 30

Represents the most rapid energy system to phosphorylate ADP to ATP

A) electron transport-oxidative phosphorylation
B) PCr
C) substrate-level phosphorylation via glycolysis
D) citric acid cycle

Question 31

Which of the following stimulates FFA liberation for energy in prolonged exercise?

A) A decrease in glucagon
B) An increase in glucagon
C) An increase in insulin
D) A decrease in epinephrine

Question 32

Moderate physical activity provide benefits as great, if not greater, __________.

A) if capillaries can constrict to reduce trunk and extremity blood flow
B) if capillaries can constrict to increase trunk blood flow
C) provided hemoglobin does not block mitochondrial transformation
D) at more intense doses

Question 33

__________ tissue releases more free fatty acids (FFAs) to active muscle as blood flow increases with exercise.

A) Renal
B) Cardiac
C) Adipose
D) Muscle

Question 34

Which of the following statements is true concerning macronutrient catabolism during physical activity?

A) The liver markedly increases its release of protein for use by active muscle as activity progresses from low to high intensity.
B) Muscle glycogen serves as the predominant carbohydrate energy source during the early stages of physical activity and as intensity increases.
C) Compared with carbohydrates and protein catabolism, lipid remains the preferential fuel during intense aerobic activity because it rapidly supplies ATP during oxidative processes.
D) In anaerobic efforts, proteins are the only contributor to ATP formation.

Question 35

During the first hour of prolonged exercise, lipid supplies about __________ of the energy, whereas during the third hour, lipid contributes up to __________ of the total energy requirement.

A) 5%, 10%
B) 90%, 30%
C) 50%, 70%
D) 50%, 50%

Question 36

Well-nourished endurance athletes rely almost completely on __________ oxidation during near-maximal, sustained aerobic effort.

A) blood glucose
B) stored glycogen
C) stored fat
D) free fatty acids

Question 37

One hour of intense exercise would significantly decrease __________ glycogen content.

A) liver
B) kidney
C) pancreas
D) nonactive muscle

Question 38

__________ stimulates glycogen breakdown in the liver and active muscle.

A) Phosphatase
B) Glycogen phosphorylase
C) Phosphofructokinase
D) Sucrase

Question 39

Compared to lipid oxidation, carbohydrate oxidation generates about __________% greater energy per unit oxygen consumed.

A) 2
B) 4
C) 6
D) 8

Question 40

Branched-chain amino acids that are oxidized in skeletal muscle rather than in liver include all of the following except __________.

A) arginine
B) leucine
C) isoleucine
D) valine

Question 41

Endurance capacity averaged about __________ times greater when subjects consumed a high-carbohydrate rather than a high-fat diet.

A) 3
B) 4
C) 5
D) 6

Question 42

Factors that justify a possible increased need for protein among those involved in exercise training include all of the following except:

A) There is an increased protein breakdown during prolonged exercise.
B) There is an increased protein breakdown during intense training.
C) There is an increased protein synthesis during exercise recovery.
D) The liver and muscles need to store protein as the primary source of exercise fuel.

Question 43

When athletes consume a high-carbohydrate diet rather than a high-fat diet, __________.

A) they often complain of nausea
B) endurance capacity tends to decrease
C) endurance capacity tends to increase
D) they often experience abdominal cramping

Question 44

Toward the end of prolonged exercise, when glycogen reserves are low, __________.

A) protein synthesis in skeletal muscles increases
B) circulating FFAs supply a greater percentage of the exercise fuel
C) exercise intensity usually increases
D) circulating insulin levels increase

Question 45

Which of the following reflects an aerobic training adaptation that enhances lipid oxidation during exercise?

A) Increased size and number of mitochondria in trained muscle
B) Decreased number of capillaries in trained muscle
C) Augmented HDL transport within the trained muscle cell
D) A decreased utilization of intramuscular triacylglycerols

Question 46

Intramuscular high-energy phosphates supply the majority of energy for intense exercise.

Question 47

A 2-hour strenuous workout greatly depletes glycogen in the liver and specifically exercised muscles.

Question 48

During 30 minutes of intense exercise, blood glucose decreases to hyperglycemic levels.

Question 49

The fuel mixture that powers physical activity generally depends on the intensity and duration of effort.

Question 50

Carbohydrate is the predominant fuel during intense aerobic exercise.

Question 51

Carbohydrate and lipid breakdown use identical pathways for acetyl-CoA oxidation.

Question 52

The relative contributions from the three energy transfer systems fall on a continuum depending on the exercise intensity and duration.

Question 53

The two main macronutrient sources that provide energy for ATP resynthesis during physical activity include liver and muscle glycogen and amino acids.

Question 54

Hypoglycemia is a blood glucose level less than 90 mg/100 mL of blood.

Question 55

With carbohydrate depletion, exercise capacity (expressed as a percentage of maximum) progressively decreases after 2 hours to 50% of the starting intensity.

Question 56

Initiation of exercise produces a prolonged decrease in plasma FFA.

Question 57

The ATP-PC systems provide about one-half of the energy required for intense exercise lasting 10 minutes, whereas aerobic reactions provide the remainder.

Question 58

For macronutrient catabolism, carbohydrate (reactions of glycolysis) becomes the sole ATP contributor in anaerobic exercise.

Question 59

The contribution of lipids is greater than carbohydrates for energy metabolism during intense exercise.

Question 60

The hormone insulin activates hormone-sensitive lipase.

Question 61

A lipid molecule is dense in terms of water content.

Question 62

Carbohydrate and protein breakdown use identical pathways for vitamin A and CoA oxidation.

Question 63

A trained muscle's augmented mitochondrial oxidative capacity and increased glycogen storage helps to explain the muscle's enhanced capacity for carbohydrate breakdown in exercise.

Question 64

Fat cells in the gluteal-femoral region represent a particularly lively area for lipolysis compared with adipocytes in the subcutaneous abdominal region.

Question 65

Maintenance of a high-protein diet stimulates adaptive responses that augment lipid utilization and consistently enhances endurance exercise performance.

Question 66

Protein's primary role is to provide amino acid building blocks for tissue synthesis.

Question 67

Regular aerobic exercise profoundly improves ability to oxidize long-chain fatty acids during mild- to moderate-intensity exercise.

Question 68

If energy intake fails to match energy expenditure during intense training, even twice the protein RDA may not maintain nitrogen balance.

Question 69

Although protein breakdown generally increases only modestly with exercise, muscle protein synthesis decreases markedly following both endurance and resistance-type exercise.

Question 70

After a few seconds of intense exercise, the glycolytic pathway generates an increasingly greater proportion of energy from carbohydrate sources.

Question 71

Exercise performances of long duration require a fairly steady energy supply derived aerobically without reliance on lactate formation.

Question 72

During anaerobic exercise, lipid becomes the sole macronutrient contributor to ATP.

Question 73

During light exercise, lipid is the macronutrient that provides the main energy substrate.

Question 74

At the same relative workload after training, women display an exaggerated shift toward lipid catabolism, whereas men do not.

Question 75

A protein-deficient diet rapidly depletes muscle and liver glycogen.

Question 76

The branched chain amino acids leucine, valine, and isoleucine are often oxidized in skeletal muscle.

Question 77

Muscle protein breakdown rises markedly after both endurance and resistance-type exercise.

Question 78

A blood glucose level below 45 mg/100 mL of blood constitutes a hypoglycemic level.

Question 79

In the body, glucose can be converted to lipid for energy storage.

Question 80

The "insulin antagonist" hormone is thyroxine.