Chapter 3 Flashcards
What is bioenergetics?
The flow of energy in a biological system via the conversion of marconutrients to usable energy.
What is catabolism?
Breakdown of large molecules into smaller, releasing energy
What is anabolism?
Synthesis of large molecules from smaller molecules, uses energy from catabolic reactions
What is an exergonic reaction?
Energy is released, typically catabolic
What is an endergonic reaction?
Energy is required, anabolic or muscle contraction.
What is metabolism?
The total of all catabolic and anabolic reactions within a system.
What drives all anabolic/exergonic reactions?
ATP.
What is hydrolysis?
Breakdown of ATP using water and ATPase, resulting in an inorganic phosphate and a hydrogen proton.
What is the only macronutrient that can be metabolized for energy without oxygen?
Carbohydrates.
Where does the phosphagen system work?
In the sarcoplasm
When is the phosphagen system used?
Short term, high intensity activities, such as sprinting and resistance training. Effective at the start of all activities.
What is used in the phosphagen system?
ADP and creatine phosphate, in the presence of creatine kinase, give off ATP and creatine.
Can phosphagen system be used for long term sustained activities?
No, due to limited creatine stores.
How much ATP is stored in the body at any one time?
80-100g.
Can ATP ever be fully depleted?
No, needed for cellular functions.
How does the phosphagen system maintain ATP concentrations?
-Creatine kinase reaction, adenylate kinase reaction.
What is the law of mass action?
Says that the concentration of reactions dictates the direction that reactions go.
Where does glycolysis occur?
Sarcoplasm
What is glycolysis?
Breakdown of carbs to synthesize ATP
Where does the glycogen for glycolysis come from?
Muscles (primary) or liver (less).
What is the rate of ATP production from phosphagen, and it’s capacity?
High rate, low capacity.
What is the rate of ATP production from glycolysis, and it’s capactiy?
Moderate rate, high capacity.
What is the end result of glycolysis?
Pyruvate
Where does pyruvate from glycolysis go?
Mitochondria if adequate oxygen, converted to lactate in sarcoplasm if not.
What limits the duration of anaerobic glycolysis?
H+ buildup and intracellular pH decrease.
What is aerobic glycolysis?
Production of glycolysis in the presence of O2 in mitochondria, slower than anaerobic but higher capacity.
What controls where pyruvate goes?
Intensity of exercise/oxygen presence
What causes metabolic acidosis?
H+ accumulation as a result of pyruvate breakdown, not lactic acid
What does metabolic acidosis do?
Lowers pH, inhibits glycolysis, interferes with excitation /contraction coupling, decreases enzyme turnover.
What is a normal lactate range at rest?
0.5-2.2 mmol/L at rest
What type of muscle fibers accumulate more lactate?
Type II
When does fatigue from lactate set in?
At 20-25 mmol/Liter
What influences lactate accumulation?
Training state, intensity, duration, muscle fiber type, initial glycogen levels.
What buffers H+ in the blood?
Bicarbonate
How does lactate get cleared?
1) Cori cycle in liver, 2) oxidation in muscle fibers
How long does it take for lactate to return to preexercise levels?
Approximately an hour, active recovery helps. Less difficulty with higher trained athletes.
When is the Krebs cycle used in glycolysis?
In the presence of oxygen
How many ATP does glycolysis net?
2 from blood glucose or 3 from muscle glycogen
What stimulates glycolysis?
High ADP, Pi, or ammonia, or slight decrease in Ph
What inhibits glycolysis?
Very low pH, ATP, CP, citrate, or fatty acids
What is the lactate threshold?
point where blood lactate behind an abrupt increase above baseline due to increased relience on anaerobic systems.
Where is the lactate threshold?
~50-70% in untrained, 70-80% of VO2 Max in trained
What is the onset of blood lactate accumulation?
Second point of inflection at higher exercise intensity.
Shift to use of larger motor units.
When is the oxidative energy system used?
Rest, prolonged low intensity activities.
What fuels does the oxidative energy system use?
Carbs and fats. Fats at rest, carbs with activity. Proteins if carbs and fats run out.
How many ATP are produced from the oxidation of one glucose?
38, 39 if from muscle glycogen.
How many ATP can be generated from fat oxidation?
300+ ATP from one lipid.
What time of protein can be used for oxidative energy if needed?
Branch-chain amino acids. Causes urea and ammonia to form, rapid fatigue.
What are the rate limiters for oxidative?
- Conversion of isocitrate to alpha ketoglutarate in Krebs,
- ATP in ETC.
What duration uses phosphagen?
0-6 seconds
What duration uses both phosphagen and fast glycolysis?
6-30 seconds
What duration uses mainly fast glycolysis
30 sec to 2 min
What duration uses fast glycolysis and oxidative?
2-3 min
What duration uses primarily oxidative?
> 3 minutes
What depletion causes fatigue in competition?
Phosphagens, gycogen.
Where is the majority of glycogen stored?
Muscle, then liver
When is glycogen used
Mod to high intensity exercise
At what duration is glycogen depleted?
> 90 min of exercise at >50% HRR
How to replenish glycogen?
- 7-3g of carbs per kg of body weight in the two hours after exercise
- may take 5-6 hours, or greater than 24 hours
What can limit performance?
Metabolic acidosis, glycogen depletion, increased P level, increased ADP, increased ammonia, impaired calcium release.
What is oxygen deficit?
Total anaerobic contribution to exercise cost
What is oxygen debt?
Excessive post exercise oxygen consumption to return to baseline levels
How long until aerobic respiration takes over in activity?
60 seconds
Work to rest ratio for 5-10 second activity?
1:12-20
Work to rest for 15-30 second activity
1:3-5
Work:rest for 1-3 minutes
1:3-4
Work:rest for 3+ minutes
1:1, 1:3
What are the nine adjustable aspects of HIIT?
- Work intensity
- Work duration
- Rest intensity
- Rest duration
- Type of exercise
- Number of repetitions
- Number of sets
- Time of rest between sets
- Intensity of rest between sets
What is the most important aspect of HIIT?
Keep close to VO2 Max for as long as possible
What is HIIT good for?
Improving VO2, proton buffering, improving glycogen content, anaerobic theshold
