Chapter 3 Bioenergetics of Exercise and Training

Question 1

What are exergonic reactions?

Answer 1

Energy releasing reactions and are generally catabolic

Question 2

What are endergonic reactions?

Answer 2

Require energy and include anabolic (build up) and the contraction of muscle

Question 3

What are the Anaerobic energy processes?

Answer 3

Phosphagen and Glycolytic

Question 4

What are the 3 Aerobic energy processes?

Answer 4

Krebs Cycle, Electron Transport Chain and Oxidative system

Question 5

What is the final chemical action during hydrolysis of ADP?

Answer 5

The hydrolysis of ADP breaks the terminal bond, releases energy and leaves AMP, P and H+

Question 6

The replenishment of ATP in human skeletal muscle is accomplished by three basic energy systems

Answer 6

Phosphagen, glycolytic, and oxidative

Question 7

T/F Are all three energy systems active during at any given time?

Answer 7

TRUE. All three energy systems are active at any given time; however the magnitude of the contribution of each system to overall work primarily dependent on the intensity of the activity and secondarily on the duration.

Question 8

What is the chemical process during the phosphagen energy system?

Answer 8

ADP + CP&raquo_space;»>««

Question 9

The Creatine Kinase Reaction

Answer 9

Provides energy at a high rate; however, because CP is stored in relatively small amounts the phosphagen system cannot be the primary supplier of energy for continuous, long duration activities.

Question 10

How much ATP can the body store at any given time?

Answer 10

80-100g (about 3 ounces) which does not represent a significant energy reserve for exercise. In addition, ATP stores cannot be completely depleted due to the necessity for basic cellular function.

Question 11

What enzyme is powerful enough to stimulate Glycolysis?

Answer 11

Adenylate Kinase also called Myokinase

Question 12

The reactions of the phosphagen system are largely controlled by?

Answer 12

The Law of Mass Action or the Mass Action Effect

Question 13

The law of mass action states

Answer 13

That the concentrations of reactants or products (or both) in solution will drive the direction of the reactions.

Question 14

What is Glycolysis?

Answer 14

Glycolysis is the breakdown of carbohydrate (sugar)-either glycogen stored in the muscle or glucose delivered in the blood to resynthesize ATP.

Question 15

Why does glycolysis produce ATP at a slower rate compared to the phosphagen system?

Answer 15

The process of glycolysis involves multiple enzyme dependent reactions

Question 16

During Glycolysis the capacity to make is much higher due to ?

Answer 16

A larger supply of glycogen and glucose compared to CP

Question 17

Where does phosphagen and glycolysis take place?

Answer 17

In the sarcoplasm of the cell

Question 18

What is the end result of glycolysis

Answer 18

Pyruvate

Question 19

What are the two directions that pyruvate can proceed

Answer 19

1) Pyruvate can be changed to lactate in the sarcoplasm

2) Pyruvate can be shuttled into the mitochondria

Question 20

Anaerobic Glycolysis

Answer 20

When Pyruvate is converted to lactate, ATP resynthesis occurs at a faster rate via the rapid regeneration of NAD+, but is limited in duration due to the subsequent H+ production and resulting decreases in pH

Question 21

Aerobic/ Slow Glycolysis

Answer 21

The ATP resynthesis rate is slower because of the numerous reactions, but can occur for a longer duration if the exercise intensity is low enough.

Question 22

The fate of pyruvate is ultimately controlled by

Answer 22

the energy demands within the cell.

Question 23

The formation of lactate from pyruvate is catalyzed by the enzyme _______ ________

Answer 23

Lactate Dehydrogenase

Question 24

Proton H+

Answer 24

accumulation during fatigue reduces the intracellular pH, inhibits glycolytic reactions and directly interferes with muscle excitation -contraction coupling-possibly by inhibiting calcium binding to troponin

Question 25

Metabolic Acidosis

Answer 25

The process of an exercise induced decrease in pH

Question 26

Why doesn't lactate cause Metabolic Acidosis

Answer 26

Lactate is utilized as an energy substrate, specifically in type 1 and cardiac fibers. It is also used during the formation of glucose from non carbohydrate sources during extended exercise and recovery. The process is called Glyconeogenesis

Question 27

Cori Cycle

Answer 27

Lactate can be cleared by oxidation with the muscle fibers in which it was produced, or it can be transported in the muscle fibers to be oxidized. Lactate can also be transported in the blood to the liver, where it is converted to glucose.

Question 28

Blood Lactate Concentration Levels

Answer 28

Return back to normal, pre-exercise values within an hour after activity, depending on the duration and intensity of exercise, training status, and type of recovery.

Question 29

Net reaction for glycolysis

Answer 29

Glucose +2Pi + 2ADP >>>>> 2Lactate +2ATP +H2O

Question 30

Net reaction for Pyruvate

Answer 30

Glucose +2Pi +2ADP + 2NAD+ >>>>> 2 Pyruvate +2ATP +2NADH + 2H2O

Question 31

Two primary mechanisms for resynthesizing ATP during Metabolism

Answer 31

1) Substrate-level phosphorylation | 2) Oxidative phosphorylation

Question 32

Phosphorylation is the process of adding an ___________ ___________ to another molecule

Answer 32

Inorganic Phosphate

Question 33

Oxidative Phosphorylation

Answer 33

refers to the resynthesis of ATP in the Electron Transport Chain

Question 34

Substrate Level Phosphorylation

Answer 34

refers to the direct resynthesis of ATP from ADP during a single reaction in the metabolic pathways.

Question 35

Step 1 for substrate level phosphorylation Step 2 for substrate level phosphorylation

Answer 35

S1) 1,3-bisphosphoglycerate + ADP + Pi>>>>>>>>>>3-phosphoglycerate +ATP S2) Pi>>>>>>>>Pyruvate + ATP

Question 36

The gross number of ATP molecules that are resynthesized as a result of substrate-level phosphorylation during glycolysis is ___

Answer 36

4

Question 37

The enzyme that converts fructose-6-phosphate to fructose -1,6-biphosphate

Answer 37

phosphofructokinase (PFK)

Question 38

Which enzyme is responsible for the phosphorylation of blood glucose

Answer 38

Hexokinase

Question 39

Two sources of glucose

Answer 39

Blood Glucose and Muscle Glycogen

Question 40

Blood Glucose and Muscle Glycogen ATP Resynthesized

Answer 40

(BG)- 2 ATP are used and 4 ATP are resynthesized which results in a net resynthesis of 2 ATP molecules. (MG)- Only 1 ATP is used and 4 ATP are resynthesized, which yields a net resynthesis of 3 ATP molecules

Question 41

is stimulated to increase during intense muscle actions by high concentrations of ADP, Pi and ammonia and by a slight decrease in pH and AMP, all of which are signs of increased ATP hydrolysis and a need for energy

Answer 41

Glycolysis Stimulation

Question 42

It is inhibited by markedly lower pH, ATP, CP, citrate and free fatty acids

Answer 42

Glysolysis Inhibition

Question 43

Concentrations of Hexokinase, PFK and Pyruvate kinase. All three are regulatory enzymes in glycolysis, because each has an important allosteric (other site) binding sites.

Answer 43

Glycolysis regulation

Question 44

Occurs when the end product of a reaction or series of reactions feeds back to regulate the turnover rate of key enzymes in the metabolic pathways.

Answer 44

Allosteric Regulation

Question 45

Occurs when an end product binds to the regulatory enzyme and decreases it's turnover rate and slows product formation

Answer 45

Allosteric Inhibition

Question 46

Occurs when an "activator" binds with the enzyme and increases it's turnover rate.

Answer 46

Allosteric Activation

Question 47

Is the most important regulator of glycolysis because it is the rate limiting step.

Answer 47

Phosphofructokinase

Question 48

Is an allosteric inhibitor of PFK; therefore, as intracellular ATP concentrations rise, PFK activity decreases and reduces the conversion of fructose 6 phosphate to fructose 1,6-biphosphate and, subsequently, decreases activity of the glycolytic pathway.

Answer 48

Adenosine Triphoshate

Question 49

The exercise intensity or relative intensity at which blood lactate begins an abrupt increase above the baseline concentration has been termed the

Answer 49

Lactate Threshold

Question 50

The ______ _______ represents a significantly increased reliance on anaerobic mechanisms for energy production to meet demand.

Answer 50

Lactate Threshold

Question 51

The Lactate Threshold begins at ___ - ____ for Untrained individuals

Answer 51

50%-60%

Question 52

The Lactate Threshold begins at ____ -____ for aerobically trained individuals

Answer 52

70%-80%

Question 53

A second increase in the rate of lactate accumulation

Answer 53

onset of blood lactate accumulation (OBLA). Occurs when the concentration of blood lactate reaches 4 mmol/L

Question 54

This system utilizes carbohydrates and fats as substrates

Answer 54

Oxidative System (>90 minutes of exercise)

Question 55

At rest

Answer 55

70% of ATP is derived from fats and 30% from carbohydrate

Question 56

The end product of Glycolysis when oxygen is sufficient, Pyruvate is

Answer 56

Transported to the Mitochondria

Question 57

A series of reactions that continues the oxidation of the substrate from glycolysis and produces 2 ATP indirectly from guanine triphosphate (GTP)

Answer 57

Krebs Cycle

Question 58

These molecules transport hydrogen atoms to the Electron Transport Chainto be used to produce ATP from ADP.

Answer 58

6 Molecules of NADH and 2 Molecules of reduced Flavin Adenine Dinucleotide (FADH2)

Question 59

During the Krebs Cycle the hydrogen atoms are passed down the chain to form a proton concentration gradient, which provides the energy for ATP production, which oxygen serving as the final electron acceptor

Answer 59

A series of electron carriers known as Cytochromes

Question 60

One molecule of NADH can produce

Answer 60

3 Molecules of ATP

Question 61

One molecule of FADH can produce 3 molecules of ATP

Answer 61

2 Molecules of ATP

Question 62

Krebs Cycle and Electron Transport Chain result in the production of ________ATP from the breakdown of one blood glucose molecule

Answer 62

38

Question 63

If the initiation of glycolysis is muscle glycogen the net ATP production is ____, since the hexokinase reaction is not necessary with muscle with muscle glycogenolysis.

Answer 63

39

Question 64

Triglycerides stored in fat cells can be broken down by an enzyme, hormone sensitive ______ to produce free fatty acids and glycerol.

Answer 64

Lipase

Question 65

Beta Oxidation

Answer 65

Free fatty acids entering the mitochondria

Question 66

Beta Oxidation

Answer 66

Hundreds of ATP molecules are produced

Question 67

Leucine, Isoleucine, Valine

Answer 67

Branched Chain Amino Acids

Question 68

Conversion of Isocitrate to a-ketoglutarate, a reaction catalyzed by the enzyme

Answer 68

isocitrate dehydrogenase

Question 69

isocitrate dehydrogenase

Answer 69

Is stimulated by ADP and and allosterically inhibited by ATP

Question 70

During exercise, the degree which anaerobic and oxidative systems contribute to the energy being produced is determined primarily by _______ _______ and secondarily by ______ _________

Answer 70

Exercise Intensity and Exercise Duration

Question 71

Energy Substrates

Answer 71

Molecules that provide starting materials for bioenergetic reactions, including phosphagens (ATP and CP) glucose, glycogen, lactate free fatty acids and amino acids

Question 72

Post Exercise phosphagen repletion can occur in relatively short period; complete resynthesis of ATP appears to occur within ____ to ____ minutes and complete CP resynthesis can occur within ____minutes

Answer 72

3 to 5 minutes 8 minutes

Question 73

Repletion of phosphagens is largely accomplished as a result of _____ ________ although glycolysis can contribute to recovery after high-intensity exercise.

Answer 73

Aerobic Metabolism

Question 74

Glycogen Storage

Answer 74

300- 400 g of glycogen are stored in the body's total muscle 70-80 g of glycogen are stored in the liver

Question 75

The rate of glycogen depletion is related to _______ _______

Answer 75

Exercise Intensity

Question 76

Post exercise glycogen repletion

Answer 76

Optimal if 0.7 to 3.0 of carbohydrate per kilogram of body weight is ingested every 2 hours following exercise

Question 77

Is a measure of a person's ability to take in oxygen

Answer 77

Oxygen Uptake

Question 78

At the start of an exercise bout, however, some of the energy must be supplied through anaerobic mechanisms because the aerobic system responds slowly to the initial increase in the demand for energy

Answer 78

Oxygen deficit

Question 79

After exercise oxygen uptake remains above pre exercise levels for a period of time that varies according to the intensity and length of exercise

Answer 79

Oxygen debt or Excess post exercise oxygen consumption

Question 80

The EPOC is the

Answer 80

Oxygen uptake above resting values used to restore the body to the pre exercise condition

Question 81

Contributions from Anaerobic mechanisms are primary up to ___ seconds

Answer 81

60 seconds

Question 82

_____ has the greatest effect on EPOC

Answer 82

Intensity

Question 83

30 second maximum cycling with 4 minutes of recovery

Answer 83

1:8 work to rest ratio

Question 84

Which substance can be metabolized anaerobically?

Answer 84

Glucose

Question 85

Which is the primary cause of metabolic acidosis?

Answer 85

ATP>>>>>>ADP + Pi + H+

Question 86

Which of the following energy systems produces ATP at the quickest rate ?

Answer 86

Phosphagen

Question 87

Approximately how many net ATP are produced via the oxidative energy system from the metabolism of one glucose molecule?

Answer 87

38

Question 88

Which of the following energy substrates cannot be depleted during extreme exercise intensities or durations?

Answer 88

ATP