Chapter 3 - Bioenergetics Flashcards
1
Q
Metabolic Specificity of Exercise and Training (3)
A
- Based on an understanding of the transfer of energy in biological systems.
- Efficient and productive training programs can be designed through an understanding of how energy is made available for specific types of exercise
- And how energy transfer can be modified by specific training regimens.
2
Q
Bioenergetics (4)
A
- The flow of energy in a biological system
- Concerns primarily the conversion of macronutrients into biologically usable forms of energy
- Macronutrients - carbs, protein, and fats - contain chemical energy
- It is the breakdown of the chemical bonds in these macronutrients that provides the energy necessary to perform biological work
3
Q
Catabolism (3)
A
- The breakdown of large molecules into smaller molecules
- Associated with the release of energy
- The breakdown of protein into amino acids is an example of catabolism
4
Q
Anabolism (4)
A
- The synthesis of larger molecules from smaller molecules
- Uses the energy released from catabolic reactions
- This is a building-up process
- The formation of protein from amino acids is an example of anabolic process
5
Q
Exergonic Reactions (2)
A
- Energy-releasing reactions
- Generally catabolic
6
Q
Endergonic Reactions (2)
A
- Requires energy
- Includes anabolic processes and the contraction of muscle
7
Q
Metabolism (1)
A
- The total of all the catabolic/exergonic and anabolic/endergonic reactions in a biological system
8
Q
Adenosine Triphosphate (ATP) (7)
A
- Classified as a high-energy molecule
- Because it stores large amounts of energy in the chemical bonds of the two terminal phosphate groups
- Allows the transfer of energy from exergonic to endergonic reactions
- Energy derived from catabolic/exergonic reactions is used to drive anabolic/endergonic reactions through this intermediate molecule, ATP
- Composed of Adenosine and 3 phosphate groups
- S&C professionals need to have a basic understanding of how exercise affects ATP hydrolysis and re-synthesis when designing training programs
- Because muscle cells store ATP only in limited amounts and activity requires a constant supply of ATP to provide the energy needed for muscle actions, ATP-producing processes must occur in the cell
9
Q
Adenosine (4)
A
- An organic compound
- The combination of adenine and ribose
- Adenine is a nitrogen-containing base
- Ribose is a five-carbon sugar
10
Q
Hydrolysis (3)
A
- The breakdown of one molecule of ATP to yield energy
- Because it requires one molecule of water
- The hydrolysis of ATP is catalyzed by the presence of an enzyme called ATPase - adenosine triphosphatase
11
Q
Adenosine Triphosphatase (ATPase)
A
- An enzyme
- The hydrolysis of ATP is catalyzed by the presence of this enzyme
12
Q
Myosin ATPase (1)
A
- An enzyme that catalyzes ATP hydrolysis for crossbridge recycling
13
Q
Calcium ATPase (2)
A
- Another specific enzyme that hydrolyzes ATP
- Pumps calcium into the sarcoplasmic reticulum
14
Q
Sodium-Potassium ATPase (2)
A
- Another specific enzyme that hydrolyzes ATP
- Maintains the sarcolemmal concentration gradient after depolarization
15
Q
What is this equation of? (6)
A
- Equation for ATP Hydrolysis
- The following equation depicts the reactants (left), enzyme (middle), and products (right)
- Reactants are Adenosine Triphosphate and Water molecule
- Enzyme is Adenosine Triphosphotase
- The products are Adenosine Diphosphate, Inorganic Phosphate, Hydrogen Ion (proton)
- The energy released primarily from the hydrolysis of ATP, and secondarily from ADP, results in biological work
16
Q
Adenosine Diphosphate (ADP)
A
- Only 2 phosphate groups
17
Q
Inorganic Phosphate (Pi)
A
- Molecule
18
Q
Adenosine Monophosphate (AMP)
A
- Further hydrolysis of ADP cleaves the second phosphate group and yields AMP
- Where cleaves means to divide
19
Q
3 Basic Energy Systems in Mammalian Muscle Cells to Replenish ATP
A
- Phosphagen System
- Glycolysis
- Oxidative System
- All 3 energy systems are active at any given time; however, the magnitude of the contribution of each system to overall work performance is primarily dependent on the intensity of the activity, and secondarily, on the duration
20
Q
Anaerobic Processes
A
- Does not require the presence of oxygen
21
Q
Aerobic Processes
A
- Depends on oxygen
22
Q
Phosphagen System
A
- Anaerobic mechanism
- Occurs in the sarcoplasm of a muscle cell
23
Q
Glycolytic Systems
A
- Anaerobic mechanism
- Occurs in the sarcoplasm of a muscle cell
24
Q
Krebs Cycle
A
- Aerobic mechanism
- Occurs in the mitochondria of muscle cells
- Requires oxygen as the terminal electron acceptor
25
Oxidative System
1. Aerobic mechanism
2. Occurs in the mitochondria of muscle cells
3. Requires oxygen as the terminal electron acceptor
26
Mitochondria
1. An organelle found in cells
2. Double membrane structure
3. Uses aerobic respiration to generate ATP
27
Macronutrients
1. Carbs, Protein, Fats
2. Only Carbs can be metabolized for energy without the direct involvement of oxygen
3. Therefore, carbohydrate is critical during anaerobic metabolism
28
Phosphagen System
1. Provides ATP primarily for short-term, high-intensity activities
2. Is highly active at the start of all exercise regardless of intensity
3. This energy system relies on the hydrolysis of ATP and breakdown of another high-energy phosphate molecule called creatine phosphate (CP)
4. Because CP is stored in relatively small amounts, the phosphagen system cannot be the primary supplier of energy for continuous, long-duration activities
5. Through CP and the creatine kinase reaction, this system serves as an energy reserve for rapidly replenishing ATP
29
Creatine Phosphate (CP)
1. A high-energy phosphate molecule
2. Also called phosphocreatine (PCr)
3. Suppkies a phosphate group that combines with ADP to replenish ATP
4. Type II muscle fibers (fast-twitch) contain higher concentrations of CP than Type I (slow-twitch) fibers
30
Creatine Kinase
1. The enzyme that catalyzes the synthesis of ATP from CP and ADP
2. This reaction provides energy at a high rate
3. The phosphogan system uses the creatine kinase reaction to maintain the concentration of ATP
31
Phosphocreatine (PCr)
1. A high-energy phosphate molecule
2. Also called creatine phosphate (CP)
32
ATP Stores
1. The body stores approx. 80 to 100g (about 3 oz) of ATP at any given time
2. ATP stores cannot be completely depleted due to the necessity for basic cellular function
3. ATP concentrations may decrease by up to 50% to 60% of the pre-exercise levels
33
Adenylate Kinase Reaction
1. A single-enzyme reaction that can rapidly replenish ATP
2. Also called myokinase reaction
3. AMP, a product of the adenylate kinase (myokinase) reaction, is a powerful stimulant to glycolysis
34
Myokinase Reaction
1. Also called adenylate kinase reaction
2. A single-enzyme reaction that can rapidly replenish ATP
3. AMP, a product of the adenylate kinase (myokinase) reaction, is a powerful stimulant to glycolysis
35
Glycolysis
1. The breakdown of carbohydrate- either glycogen store in the muscle or glucose delivered in the blood- to resynthesize ATP
2. The process involves multiple enzymatically catalyzed reactions
3. As a result, the ATP resynthesis rate during glycolysis is not as rapid as with the single-step phosphagen system
4. However, the capacity to produce ATP is much higher due to a larger supply of glycogen and glucose compared to CP
5. Occurs in the sarcoplasm
36
Law of Mass Action
1. The reactions of the phosphagen system are largely controlled by the law of mass action
2. Also known as the mass action effect
3. The concentrations of reactants or products (or both) in solution will drive the direction of the reactions
4. With enzyme-mediated reactions, such as the reactions of the phosphagen system, the rate of product formation is greatly influenced by the concentrations of the reactants
37
Pyruvate
1. The end result of glycolysis
2. Can be converted to lactate in the sarcoplasm
3. Also can be shuttled into the mitochondria, to undergo the Krebs cycle
4. The fat of pyruvate is ultimately controlled by the energy demands within the cell
5. If energy demand is high and must be transferred quickly, as during resistance training, pyruvate is primarily converted to lactate for further support of anaerobic glycolysis
6. If energy demand is not as high and oxygen is present in the cell, pyruvate can be further oxidized in the mitochondria
38
Anaerobic Glycolysis
1. When pyruvate is converted to lactate, ATP resynthesis occurs at a faster rate
2. But is limited in duration due due to the subsequent H+ production and resulting decrease in cytosolic pH
3. Also known as fast glycolysis
39
Aerobic Glycolysis
1. Also known as slow glycolysis
2. When pyruvate is shuttled into the mitochondria to undergo the Krebs cycle, the ATP resynthesis rate is slower because of the numerous reactions
3. But it can occur for a longer duration if exercise intensity is low enough
4. However, because glycolysis itself does not depend on oxygen, the terms anaerobic and aerobic glycolysis are probably not practical
40
Metabolic Acidosis
1. The process of an exercise-induced decrease in pH
2. May be responsible for much of the peripheral fatigue during exercise
41
Gluconeogenesis
1. The formation of glucose from noncarbohydrate sources - during extended exercise and recovery
42
Wet Muscle
1. Muscle that has not been desiccated
43
Cori Cycles
1. The process where lactate is transported in the blood to the liver, where it is converted to glucose
44
Lactic Acidosis
45
Nicotinamide Adenine Dinucleotide (NADH)
46
Glycolysis Leading to the Krebs Cycle
47
Two Primary Mechanisms for Re-synthesizing ATP
48
Phosphorylation
49
Oxidative Phosphorylation
50
Electron Transport Chain (ETC)
51
Substrate-Level Phosphorylation
52
Phosphofructokinase (PFK)
53
Glycogenolysis
54
Control of Glycolysis
55
Allosteric Inhibition
56
Allosteric Activation
57
Rate-Limiting Step
58
Lactate Threshold (LT)
59
Oxygen Uptake in Lactate Threshold
60
Onset of Blood Lactate Accumulation (OBLA)
61
The Oxidative (Aerobic) System
62
Flavin Adenine Dinucleotide (FADH2)
63
Cytochromes
64
Fat Oxidation
65
Fatty Acids & Beta Oxidation
66
Protein Oxidation
67
Branched-Chain Amino Acids
68
Control of the Oxidative (Aerobic) System
69
Substrate Depletion
70
Repletion
71
Rate of Glycogen Depletion
72
Oxygen Uptake
73
Oxygen Deficit
74
Oxygen Debt
75
Excess Post-Exercise Oxygen Consumption (EPOC)
76
Aerobic Exercise and EPOC
77
Resistance Exercise and EPOC
78
Factors Responsible for EPOC
79
Metabolic Specificity of Training
80
Interval Training
81
Work-to-Rest Ratios
82
High-Intensity Interval Training (HIIT)
83
9 HIIT Variables (to be manipulated)
84
Combination Training
85
Using Interval Training to Train Specific Energy Systems
86
Lactic Acid
87
Lactate
1. Lactate is the product of the lactate dehydrogenase reaction
2. Although the muscular fatigue experienced during exercise often correlates with high tissue concentrations of lactate, lactate is not the cause of fatigue
3. Often used as an energy substrate, especially in Type I and cardiac muscle fibers
4. It is also used in gluconeogenesis
5. Normally, there is a low concentration of lactate in blood and muscle
6. Normal range of lactate concentration in blood is 0.5 to 2.2 mmol/L at rest
7. And 0.5 to 2.2 mmol for each kilogram of wet muscle
8. Lactate production increases with exercise intensity
