Chapter 3 - Bioenergetics Flashcards
Metabolic Specificity of Exercise and Training (3)
- 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.
Bioenergetics (4)
- 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
Catabolism (3)
- 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
Anabolism (4)
- 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
Exergonic Reactions (2)
- Energy-releasing reactions
- Generally catabolic
Endergonic Reactions (2)
- Requires energy
- Includes anabolic processes and the contraction of muscle
Metabolism (1)
- The total of all the catabolic/exergonic and anabolic/endergonic reactions in a biological system
Adenosine Triphosphate (ATP) (7)
- 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
Adenosine (4)
- An organic compound
- The combination of adenine and ribose
- Adenine is a nitrogen-containing base
- Ribose is a five-carbon sugar
Hydrolysis (3)
- 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
Adenosine Triphosphatase (ATPase)
- An enzyme
- The hydrolysis of ATP is catalyzed by the presence of this enzyme
Myosin ATPase (1)
- An enzyme that catalyzes ATP hydrolysis for crossbridge recycling
Calcium ATPase (2)
- Another specific enzyme that hydrolyzes ATP
- Pumps calcium into the sarcoplasmic reticulum
Sodium-Potassium ATPase (2)
- Another specific enzyme that hydrolyzes ATP
- Maintains the sarcolemmal concentration gradient after depolarization
What is this equation of? (6)
- 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
Adenosine Diphosphate (ADP)
- Only 2 phosphate groups
Inorganic Phosphate (Pi)
- Molecule
Adenosine Monophosphate (AMP)
- Further hydrolysis of ADP cleaves the second phosphate group and yields AMP
- Where cleaves means to divide
3 Basic Energy Systems in Mammalian Muscle Cells to Replenish ATP
- 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
Anaerobic Processes
- Does not require the presence of oxygen
Aerobic Processes
- Depends on oxygen
Phosphagen System
- Anaerobic mechanism
- Occurs in the sarcoplasm of a muscle cell
Glycolytic Systems
- Anaerobic mechanism
- Occurs in the sarcoplasm of a muscle cell
Krebs Cycle
- Aerobic mechanism
- Occurs in the mitochondria of muscle cells
- Requires oxygen as the terminal electron acceptor
Oxidative System
- Aerobic mechanism
- Occurs in the mitochondria of muscle cells
- Requires oxygen as the terminal electron acceptor
Mitochondria
- An organelle found in cells
- Double membrane structure
- Uses aerobic respiration to generate ATP
Macronutrients
- Carbs, Protein, Fats
- Only Carbs can be metabolized for energy without the direct involvement of oxygen
- Therefore, carbohydrate is critical during anaerobic metabolism
Phosphagen System
- Provides ATP primarily for short-term, high-intensity activities
- Is highly active at the start of all exercise regardless of intensity
- This energy system relies on the hydrolysis of ATP and breakdown of another high-energy phosphate molecule called creatine phosphate (CP)
- Because CP is stored in relatively small amounts, the phosphagen system cannot be the primary supplier of energy for continuous, long-duration activities
- Through CP and the creatine kinase reaction, this system serves as an energy reserve for rapidly replenishing ATP
Creatine Phosphate (CP)
- A high-energy phosphate molecule
- Also called phosphocreatine (PCr)
- Suppkies a phosphate group that combines with ADP to replenish ATP
- Type II muscle fibers (fast-twitch) contain higher concentrations of CP than Type I (slow-twitch) fibers
Creatine Kinase
- The enzyme that catalyzes the synthesis of ATP from CP and ADP
- This reaction provides energy at a high rate
- The phosphogan system uses the creatine kinase reaction to maintain the concentration of ATP
Phosphocreatine (PCr)
- A high-energy phosphate molecule
- Also called creatine phosphate (CP)
ATP Stores
- The body stores approx. 80 to 100g (about 3 oz) of ATP at any given time
- ATP stores cannot be completely depleted due to the necessity for basic cellular function
- ATP concentrations may decrease by up to 50% to 60% of the pre-exercise levels
Adenylate Kinase Reaction
- A single-enzyme reaction that can rapidly replenish ATP
- Also called myokinase reaction
- AMP, a product of the adenylate kinase (myokinase) reaction, is a powerful stimulant to glycolysis
Myokinase Reaction
- Also called adenylate kinase reaction
- A single-enzyme reaction that can rapidly replenish ATP
- AMP, a product of the adenylate kinase (myokinase) reaction, is a powerful stimulant to glycolysis