Bioenergetics and ATP

Question 1

direct calorimetry

indirect calorimetry

closed and open example

Answer 1

All metabolic processes within the body ultimately result in heat production
* The coils absorb the heat produced and radiated by the participant
* Suit calorimeter, Air flow calorimeter

Measuring oxygen consumption providing an estimate of energy expenditure
5kcal/L of oxygen

closed, douglas bags, breath expelled air into a bag, an then analyze it, low error, but leakages, wear and tear, and costly lab setup are all dray back
open circuit, analysis breath by breath, measured from tiny samples from a mouthpiece. automated gas collection. Less accurate measurements at higher frequencies, adds breathing resistance

Question 2

Using carbs, fats, and proteins in excercise

Answer 2

How much carbohydrate is used during exercise depends on:
* Carb availability
* Development of carb metabolism in the muscle
* All carbs are eventually converted to a 6-carbon sugar (glucose) transported through the blood to muscles
* In resEng condiEon, carb is stored in muscle and liver in the form of glycogen
* Stored glycogen is limited
* Glycogen can be converted to glucose as needed

The main source of energy during prolonged and low-intensity exercise
* Fat metabolism yields more energy (9.4 kcal/g vs. 4.1 kcal/g for carb)
* However, fat metabolism is slower than carb because it should be reduced from its complex form (triglyceride) to free fatty acids (FFA) and
then further processed in the beta-oxidation system
* FFA is the only form of fat that could be used by the mitochondria

A minor energy source
* Up to 10% of energy during prolonged exercise
* Only useable under certain circumstances
* Severe energy depletion
* Starvation
* Before it is used in the cell, protein must first be
converted into glucose (gluconeogenesis) or FFA
(lipogenesis)
* Only the building blocks of the protein (amino acids) can be
used for gluconeogenesis and lipogenesis
* Produces 4.1 kcal/g

Question 3

RER in fats and carbs
what numbers should be when

lipid vs carbs as fuel

cals/L

Answer 3

Oxygen uptake: VO2
* A rate (L/min or mL/min)
* Carbon dioxide producLon: VCO2
* A rate (L/min or mL/min)
* Respiratory exchange raLo (RER)
* Carbon dioxide produced / Oxygen consumed
* RER = VCO2 / VO2

RER = VJCO2 / VJO2
* If RER = 1.0, carbohydrate is the fuel
* If RER = 0.71, lipid is the fuel
* If 1.0 > RER > 0.71, the fuel is a mix of carbohydrate and lipid
* 5.05 kcal / L O2 CARBS
* 4.69 kcal / L O2 FATS

Question 4

ATP use in muscles
% of myosin ATPase, SERCA, nak ATPase

[ATP] during exercise

sources of ATP

Answer 4

Myosin ATPase – 75%
* Dissociating myosin actin cross-bridges
* Sarco-endoplasmic reticulum ATPase (SERCA) – 25%
* Ca 2+ re-uptake
* Na+/K+ ATPase – 5%
* Rebalancing ions across the cell membrane

not much decline in concentration of ATP, resynthesized fast

PGA
Immediate system
* - - ADP and creatine phosphate
Anaerobic / Glycolytic system
* - - Glycogenolysis & glycolysis
* - - Lactate production
Aerobic / Oxidative system
* - -Carbohydrate, lipid, protein, lactate
* - - Oxidative phosphorylation