Week 08 - Energy Expenditure Flashcards
Work =
Work = Force x distance
Power =
Power = work / time
1 L O2 = ___ kcals if 100% CHO
5.1 kcals (CHO)
1 L O2 = ____ kcals if 100% fat
4.7 kcals (fat)
Complete oxidation of 1 gram of fat requires ____ oxygen than the amount of CO2 produced
more
Complete oxidation of 1 gram of CHO requires _____ oxygen as the amount of CO2 it produces
the same amount
Exergonic =
process that release (frees up) energy into its surroundings
Endergonic =
stores or absorbs energy
Enzymes =
protein that catalyses a biological reaction
Enzymes & co-enzymes function as (3):
- biological catalysts
- couplers
- regulators of metabolism
Factors influencing enzyme function (3):
- pH
- Temperature
- Availability of substrate and enzyme
Does anaerobic energy system require O2?
No
Does aerobic energy system require O2?
Yes
Where does anaerobic system occur?
sarcoplasm
Where does aerobic system occur?
mitochondria
2 disadvantages of the phosphocreatine system (PCr)
- limited capacity
- Total amount of energy available is small
Adenylate kinase in important during _____ ????
High intensity exercise
Foods contain energy in… (3)?
- CHO
- Protein
- fat
1 calorie expresses the quantity of energy needed to raise ….?
1 ml of water by 1 C
1 joule expresses the quantity of energy needed to move…?
1g at a velocity of 1 m/s
Rate of O2 consumed is directly related to …?
Rate of energy produced
Closed circuit spirometry describes…
breathe through mouthpiece, CO2 gets trapped, O2 consumed decrease O2 in spirometer, Change in volume is measured and O2 uptake is used to calculate EE
Open circuit spirometry describes….
- measured breathing ambient air
- EE is measured from O2 and CO2 content of inspired and expired air
Indirect calorimetry…?
- Douglas bag
- Breath-by-breath systems: measure volume at mouth piece, small gas sample is collected at every expiration
What percentage of energy expenditure is the resting metabolic rate (RMR) using?
40-75%
What percentage of energy expenditure is diet induced thermogenesis using?
10%
Resting metabolic rate is…
Energy required for normal functions and homeostasis under resting conditions
The largest component of energy expenditure is….
Resting metabolic rate (60-75%)
Factors can influence your RMR(3)?
- sympathetic nervous system
- thyroid hormone activity
- sodium potassium pump activity
liver, gut, brain, kidney uses ___% of energy
75% (even though only 10% BW)
Skeletal muscle uses ____% of energy
20% (and 40% BW)
Does resting metabolic rate increase or decrease with age?
Decrease
Men have ____ RMR’s than women
higher (due to mass)
Charles law:
- increase temp causes increase molecular movement
- gas expands with heat
Boyles law:
- inverse relationship with pressure
- decreased volume = increase pressure
The smallest contractile unit of of muscle fibres is the…
Sarcomere
Gibbs ‘free energy’ determines….
Whether a reaction will happen spontaneously or not
ΔG <0 =
- occurs by itself (favoured)
- exergonic
ΔG >0 =
- Cannot occur by itself (not favoured)
- Endogonic
ΔG = 0…?
- No free energy CHANGE
- Reactor is in equilibrium
ATP in skeletal muscle is ___mmol/kg of wet muscle weight
4-5mmol/kg (can only be sustained a few seconds)
What is the fastest way to get ATP resynthesised?
Through the phosphocreatine system (PCr)
PCr in muscle is ____x greater than ATP
3-4x
The phosphocreatine system results in ____kj per mole of PCr
43kj
The phosphocreatine system is good for _____
power
aerobic glycolysis makes ___ ATP, ___ NADH, and ____ FADH
4 ATP, 10 NADH, 2 FADH
The number of ATP produced depends on….
- Which system transports NADH and H+ into mitochondria
- ATP per yield calculation that is performed
