quiz #1- bioenergetics
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What is bioenergetics?
metabolic process of converting food into energy used to perform biological fxns
What is the energy expenditure for healthy adults at rest and exercise?
- rest: 1.2-1.5kcal/min
- exercise: 15-30kcal/min
breakdown of large molecules into smaller molecues --> release energy
synthesis of larger molecules from smaller ones
energy releasing reactions (catabolic)
What is the difference between glucogenesis and glycogenolysis?
Glucogenesis is the formation of glycogen by linking glucose molecules together, whereas glycogenolysis is the breakdown of glycogen into glucose
synthesis of glucose from glycerol, amino acids, and lactate
metabolic pathway in cells which glucose is degraded into pyruvate or lactate
breakdown of triglycerides in adipose tissue to free fatty acids and glycerol for transport ot tissues for metabolism
Define beta oxidation:
breakdown of fatty acids to form acetyl CoA
What are three fuels used for exercise and which are the primary ones?
- CHO and Fat are primary
What are two way CHO is fuel for exercise?
- glucose in blood
- glycogen stored in muscles nad liver
What is the significance of this: 3FA + glycerol : lypolysis
- Fa transported to skeletal muscle to fuel contraction
- glycerol: indirect fuel for muscle contraction
What are the two primary ATP sources for anaerobic?
- intramuscular stores of ATP (storage enough to fuel <3 sec
- ATP-PCr (phosphocreatine): simple and most rapid production of ATP, primarily for high intensity short term activity (5-8 sec)
What does PCr formation require?
requires ATP and occurs only during recovery- why you need 2-3 minutes of recovery
What is 3rd anerobic pathway that is the main source of energy early on when high energy phosphates are depleted?
glycolysis- primary fuel for high intensity 10-30 seconds
What are the two phases of glycolysis?
- energy investment: requires ATP, ATP is phostphate donor
- energy generation: generates ATP
What occurs if there is or is not oxygen available for energy generation in anerobic pathway of glycolysis?
- NO oxygen: H is taken from NADH, pyruvic acid is made and lactic acid frees up NAD so glycolysis can continue
- IS oxygen: pyruvic acid enters the KREB cycle directly or is converted to Acetyl Coa and enters KREB
What are the four methods (?) of aerobic metabolism?
- glycolysis: 6-8 ATPs
- generation of acetyl CoA: 14 ATPs
- Krebs Cycle: 36 ATPs
- Oxidative Phosphorylation in ETC: ATP, Co2, H2O final products
Why is lactic acid necessary?
- for glycolysis to continue
- transported to liver to convert to glucose or glycogen
- used by skeletal muscle and heart as energy substrate
When does lactic acide beome a problem?
only when it accumulates and inhibits PFKinase and lipolysis
How is Acetyl CoA formed?
breakdown of CHO, free fatty acids, and proteins
What is McArdle's Disease?
deficiency of skeletal muscle enzyme phophorylase so cant use CHO for exercise
Where does the body get its fuel for exercise?
- ATP in muscles and ATP-PCr for initial exercise
- Glycolysis for early exercise
- protein is NOT major source of energy during exercise
Where does fuel for rest come from?
- energy from aerobic metabolism of fat but carbs also
- 70% fat
- 30 % carbs
As VO2 max increases does the use of CHO or fats increase
- CHO starts low, ends high (CHO ONLY fuel for MAX work)
- Fat starts high, ends low
- high intensity >70% VO2 CHO
- low intensity <30% VO2 fats
As time duration increases does the use of CHO or fats increase:
- CHO starts high and ends low
- Fat starts low and ends high
Who burns more fat in submax workout, the trained or untrained?
well trained individual will use more fat, and less CHO than untrained person
What does fat burn in?
- the flame of the carbs...
- diminished glycogen stores result in a decrease in the rate of ATP production from fat metabolism
What happens in prolong exercise?
- > 30 minutes: low intensity, fat>carbs
- > 2 hours: gylcogen is depletes, kreb cylce intermediates reduced
- 3-5 hours: prtoein may reach 5-15% (under 2% in an hour of exercise)
1 lb fat = _____kcal
What is respiratory exchange rate?
% contribution of CHO and fat to energy metabolism during steady state exercise
- r= .85: =CHO and fat
- r<.85: fat>CHO
- r>.85: CHO>fat
What is EPOC?
- Excess Post Oxygen Consumption
- =oxygen debt
- magnitude and duration of EPOC is influence d by intensity of exercise
What is EPOC used for:
- replenish ATP, PC, and O2 stored in muscle
- supply additional oxygen where needed to ^ HR and BP post exercise
What is VO2 max?
greatest rate of oxygen uptake by body
what effects Vo2 max?
- ability of CV system to deliver oxygen to contracting muscle
- ability of muscles to take up oxygen and produce ATP aerobicallys
- genetics and exercise training
What is OBLA
- onset of blood lactate accumlation
- when blood levels of lactic acid increase exponentially
What is OBLA in trained and untrained peopel?
What are factors contributing to OBLA?
- hypoxia in muscles
- accelerated glycolysis (can't move H's quick enought to ETC)
- ^ recruitment of FT fibers (FT fibers promote conversion of pyruvic acid to lactic acid)
- decrease rate of lactate removal
How do you increase OBLA?
- work at or slightly above OBLA for 20-50 minutes
- interval training
- in the field exercise at lactate threshold corresponds to ventilation threshold
What are the 3 relief intervals?
- 1:3: for immediate energy systems (anaerobic training)
- 1:2: for glycolysis
- 1:1: for aerobic systems
How to recover in submax or max exercise:
- Submax: little or no lactic acid accumulation so passive recovery best
- Max: activity recovery best for lactic acid removal at about 35-60% VO2 max
What are metabolic adaptations of aerobic training?
- ^ in # and size of mitochondira
- 2x increase in aerobic system enzymes
- muscle fiber type and size
What are changes in VO2 max that will occur with endurance training?
- VO2 max will increase 15% with training (can increase up to 40% in untrained individuals)
- 50% Vo2 max change come from ^ in max CO
- 50% VO2 max change comes from ^ in systemic a-vO2 difference
What are metabolic adaptations of anerobic training?
- ^ anaerobic energy susbtrates
- ^ enzymes for anaerobic energy pathway (FT fibers)
- ^ capacity to generate and tolerate ^ blood lactate levels during max exercise
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