BPK 310 Midterm questions with
complete solutions A+
Define "energy expenditure." - correct answer ✔✔∙Energy Expenditure→ the total amount of
energy (gross) expended during exercise, including the resting energy expenditure (resting
energy expenditure + exercise energy expenditure). Energy expenditure may be articulated in
METs, kilocalories, or kilojoules.
Differentiate between physical activity, exercise, and physical fitness. - correct answer
✔✔∙Physical activity→ and bodily moment produced by skeletal muscular that results in
energy expenditure above resting levels. It encompasses exercise, sports, and physical activities
done as part of daily living, occupation, leisure, and active transportation
∙Exercise→ physical activity that is planned, structured, and repetitive and that has a final or
immediate objective the improvement or maintenance of physical fitness
∙Physical fitness→ the ability to carry out daily tasks with visor and alternates, without undue
fatigue and with ample energy to enjoy leisure pursuits and to meet unforeseen emergencies
What is bioenergetics? What does it consist of? - correct answer ✔✔∙The science of energy
transductions in biological systems
∙"Understanding what energy is and how the body acquires, converts, stores, and utilizes it is
the key to understanding how the body performs in sports, recreational, and occupational
activities"
∙...applied physical chemistry (thermodynamics, kinetics)
→Thermodynamics: whether a reaction will occur and its direction
→Kinetics: the rate at which the reaction occurs
What are the basic principles of bioenergetics? Explain. - correct answer ✔✔∙Energy→ is the
capacity to do work
∙Work→ transfer of energy by means other than heat
,(Mechanical): product of force acting through a given distance
→Also chemical, electrical, osmotic work
What type of work does muscle contraction represent? - correct answer ✔✔∙Chemical energy
(ATP hydrolysis) > kinetic energy (myosin conformation change, shortening of muscle)
Explain the concept of power. - correct answer ✔✔∙Power is rate of work, or work/time
∙It is the rate of energy transfer (work/time, force x velocity)
∙Maximum sustainable power determines performance
→Power is the main way to quantify physical activity (the fitter you are, the more work you can
do at a faster rate)
Explain the power-duration relationship in terms of human performance and exercise tolerance.
- correct answer ✔✔∙Peak power= maximum demand
∙Energy stores= maximum energy supply
→As duration increases, the amount of power you can sustain decreases
∙Think in terms of energy systems (ATP and CP- can generate lots of ATP quickly but not
sustainable, Anaerobic glycolysis- max power is lower than ATP and CP but has a higher capacity,
Oxidative- the power is less but the capacity is much larger again
What is more important to physical performance & health- the ability to generate power or
work? - correct answer ✔✔∙If you are not doing work at a fast enough rate, you cannot
perform. Power is probably the most important.
Distinguish power and capacity. Describe their implications for sprint and endurance
performance. - correct answer ✔✔∙In sprinting, you would generate high power and low
capacity
∙Endurance performance, you would generate lower power but have a much higher capacity.
,→Maximum aerobic power is the fastest you can use aerobic energy stores
What is a closed system vs an open system in terms of thermodynamics? What are the 2 laws of
thermodynamics? - correct answer ✔✔∙Closed system→exchanges neither matter no energy
with its surroundings
∙Open system→exchanges can occur
∙1st Law→energy of the universe is constant (not created or destroyed)
∙2nd Law→all processes incase entropy
What is enthalpy? Why is it important? - correct answer ✔✔∆H= ∆G + T∆S
∙∆H→ enthalpy change= heat transferred (units= J/mol)
∙∆G→ Gibbs free energy (energy available to do work, ie. exercise (units= J/mol))
∙T∆S→ energy unavailable to do work, "measure of disorder" of a system (units= J/mol K)
(This is the relationship between thermodynamic quantities at a constant temperature and
pressure)
Endergonic rxn: ∆G>0 (consumes free energy)
Exergonic rxn: ∆G<0 (releases free energy)
Endothermic rxn: ∆H>0 (increase enthalpy of the system)
Exothermic rxn: ∆H<0 (decrease enthalpy of the system)
How does the free energy of a system determine the direction of the reaction? - correct answer
✔✔In chemical transformations, the standard free energy is the free energy released as 1M of
reactants and products proceed to equilibrium concentrations
∆G⁰'=-RTlnK(eq)
, Keq'=([C]^c*[D]^d)/([A]^a*[B]^b)
∙if Keq>1, ∆G<0, proceeds forward
∙if Keq=1, ∆G=0, equilibrium
∙if Keq<1, ∆G>0, proceeds in reverse
How do you calculate the actual free-energy change of a reaction? - correct answer ✔✔∙Need
to know the mass-action ratio (depends on the reactant and product [ ]'s and the temperature)
∆G=∆G⁰' + RTln([products]/[reactants])
→is the theoretical amount of work the reaction can do assuming 100% efficiency
MAR= ([C]^c[D]^d/[A]^a[B]^b)
→when reaction components are NOT at equilibrium, this ratio is the mass-action ratio
Actual free energy change:
∆G= ∆G⁰' + RTlnMAR
What is the most common chemical intermediate for yielding energy in the body? - correct
answer ✔✔Adenosine triphosphate→ terminal phosphate bond is hydrolyzed to provide energy
What factors determine the actual free energy change in ATP hydrolysis in a muscle cell? -
correct answer ✔✔∙ATP and ADP exist as MgATP² and MgADP ([ ]'s << 1M)
SLIFE 29
How does free energy of ATP hydrolysis vary with temperature and pH? - correct answer
✔✔∙H⁺ ions participate in the reactions such that pH is a factor (normal muscle pH is 7.5, in
intense exercise is can ↓ to 6.5-6.6)...so the more acidic, the less free energy released
∙The acidity is due to ATP hydrolysis and NOT lactate
∙Less overall energy to power muscle contraction with increased acidity
complete solutions A+
Define "energy expenditure." - correct answer ✔✔∙Energy Expenditure→ the total amount of
energy (gross) expended during exercise, including the resting energy expenditure (resting
energy expenditure + exercise energy expenditure). Energy expenditure may be articulated in
METs, kilocalories, or kilojoules.
Differentiate between physical activity, exercise, and physical fitness. - correct answer
✔✔∙Physical activity→ and bodily moment produced by skeletal muscular that results in
energy expenditure above resting levels. It encompasses exercise, sports, and physical activities
done as part of daily living, occupation, leisure, and active transportation
∙Exercise→ physical activity that is planned, structured, and repetitive and that has a final or
immediate objective the improvement or maintenance of physical fitness
∙Physical fitness→ the ability to carry out daily tasks with visor and alternates, without undue
fatigue and with ample energy to enjoy leisure pursuits and to meet unforeseen emergencies
What is bioenergetics? What does it consist of? - correct answer ✔✔∙The science of energy
transductions in biological systems
∙"Understanding what energy is and how the body acquires, converts, stores, and utilizes it is
the key to understanding how the body performs in sports, recreational, and occupational
activities"
∙...applied physical chemistry (thermodynamics, kinetics)
→Thermodynamics: whether a reaction will occur and its direction
→Kinetics: the rate at which the reaction occurs
What are the basic principles of bioenergetics? Explain. - correct answer ✔✔∙Energy→ is the
capacity to do work
∙Work→ transfer of energy by means other than heat
,(Mechanical): product of force acting through a given distance
→Also chemical, electrical, osmotic work
What type of work does muscle contraction represent? - correct answer ✔✔∙Chemical energy
(ATP hydrolysis) > kinetic energy (myosin conformation change, shortening of muscle)
Explain the concept of power. - correct answer ✔✔∙Power is rate of work, or work/time
∙It is the rate of energy transfer (work/time, force x velocity)
∙Maximum sustainable power determines performance
→Power is the main way to quantify physical activity (the fitter you are, the more work you can
do at a faster rate)
Explain the power-duration relationship in terms of human performance and exercise tolerance.
- correct answer ✔✔∙Peak power= maximum demand
∙Energy stores= maximum energy supply
→As duration increases, the amount of power you can sustain decreases
∙Think in terms of energy systems (ATP and CP- can generate lots of ATP quickly but not
sustainable, Anaerobic glycolysis- max power is lower than ATP and CP but has a higher capacity,
Oxidative- the power is less but the capacity is much larger again
What is more important to physical performance & health- the ability to generate power or
work? - correct answer ✔✔∙If you are not doing work at a fast enough rate, you cannot
perform. Power is probably the most important.
Distinguish power and capacity. Describe their implications for sprint and endurance
performance. - correct answer ✔✔∙In sprinting, you would generate high power and low
capacity
∙Endurance performance, you would generate lower power but have a much higher capacity.
,→Maximum aerobic power is the fastest you can use aerobic energy stores
What is a closed system vs an open system in terms of thermodynamics? What are the 2 laws of
thermodynamics? - correct answer ✔✔∙Closed system→exchanges neither matter no energy
with its surroundings
∙Open system→exchanges can occur
∙1st Law→energy of the universe is constant (not created or destroyed)
∙2nd Law→all processes incase entropy
What is enthalpy? Why is it important? - correct answer ✔✔∆H= ∆G + T∆S
∙∆H→ enthalpy change= heat transferred (units= J/mol)
∙∆G→ Gibbs free energy (energy available to do work, ie. exercise (units= J/mol))
∙T∆S→ energy unavailable to do work, "measure of disorder" of a system (units= J/mol K)
(This is the relationship between thermodynamic quantities at a constant temperature and
pressure)
Endergonic rxn: ∆G>0 (consumes free energy)
Exergonic rxn: ∆G<0 (releases free energy)
Endothermic rxn: ∆H>0 (increase enthalpy of the system)
Exothermic rxn: ∆H<0 (decrease enthalpy of the system)
How does the free energy of a system determine the direction of the reaction? - correct answer
✔✔In chemical transformations, the standard free energy is the free energy released as 1M of
reactants and products proceed to equilibrium concentrations
∆G⁰'=-RTlnK(eq)
, Keq'=([C]^c*[D]^d)/([A]^a*[B]^b)
∙if Keq>1, ∆G<0, proceeds forward
∙if Keq=1, ∆G=0, equilibrium
∙if Keq<1, ∆G>0, proceeds in reverse
How do you calculate the actual free-energy change of a reaction? - correct answer ✔✔∙Need
to know the mass-action ratio (depends on the reactant and product [ ]'s and the temperature)
∆G=∆G⁰' + RTln([products]/[reactants])
→is the theoretical amount of work the reaction can do assuming 100% efficiency
MAR= ([C]^c[D]^d/[A]^a[B]^b)
→when reaction components are NOT at equilibrium, this ratio is the mass-action ratio
Actual free energy change:
∆G= ∆G⁰' + RTlnMAR
What is the most common chemical intermediate for yielding energy in the body? - correct
answer ✔✔Adenosine triphosphate→ terminal phosphate bond is hydrolyzed to provide energy
What factors determine the actual free energy change in ATP hydrolysis in a muscle cell? -
correct answer ✔✔∙ATP and ADP exist as MgATP² and MgADP ([ ]'s << 1M)
SLIFE 29
How does free energy of ATP hydrolysis vary with temperature and pH? - correct answer
✔✔∙H⁺ ions participate in the reactions such that pH is a factor (normal muscle pH is 7.5, in
intense exercise is can ↓ to 6.5-6.6)...so the more acidic, the less free energy released
∙The acidity is due to ATP hydrolysis and NOT lactate
∙Less overall energy to power muscle contraction with increased acidity
