9-25c Metabolic Pathways for Aerobic Exercise Flashcards
What chemical pathways does m. use to regenerate ATP?
glycolysis > pyruvate or lactate
creatine shuffle
oxidative phosphorylation > ETC > Krebs Cycle
Describe the fuel sources used to drive energy pathways
e
Describe the energy pathways employed at rest and during exercise?
e
Describe the metabolic adaptations to training
e
What are the key characteristics to each of the chemical pathways?
e
What fuel sources are available to power oxidative phosphorylation? When are they most utilized?
Lipids: at rest
glucose & glycogen (carbohydrates): heavy exercise
protein: disease states and starvation
How do the different fuel sources compare?
Lipids > broken down via lipolysis > glycerol and free fatty acids
Free fatty acids > beta oxidation cycle (huge capacity of 100k kcal and 130 ATP/mol. palmitic acid
glycerol > glycolysis > CAC > ETC
glucose or glycogen (burned more @ high intensity) > glycolysis > pyruvate > TCA > ETC (36 ATP per mol. glucose), since less glucose is stored, only 500 kcal per m. glycogen
protein > aa > deamination > enter at various points of glycolysis and TCA cycle > ETC > ATP (mod capacity w/ 24kcal in m. protein), minor source of energy during exercise, can be used in gluconeogenesis
How does ATP concentration remain the same?
ATP is regenerated just as quickly to maintain homeostasis
What is: the time to max rate the max power (kcal/min) max capacity (kcal) O2 required for Phosphocreatine?
fast (immediate)
High power (36)
low (11)
No
What is: the time to max rate the max power (kcal/min) max capacity (kcal) O2 required for Anaerobic Glycolysis?
5-10 sec
16 (moderate)
15 (moderate)
No
What is: the time to max rate the max power (kcal/min) max capacity (kcal) O2 required for Oxidative Phosphorylation?
2-3 mins
10 (low)
2000 (high)
Yes
What is: the time to max rate the max power (kcal/min) max capacity (kcal) O2 required for Oxidative Phosphorylation?
2-3 mins
10 (low)
2000 (high)
Yes
What is the phosphocreatine reaction?
ADP + PCr + H+ >creatine kinase> ATP + Cr
What is: the time to max rate the max power (kcal/min) max capacity (kcal) O2 required for Phosphocreatine? What length and power of activities? When is it a key player in ATP production?
fast (immediate) High power (36) low capacity (11) No Short term but high power trans. from rest to exercise
What is: the time to max rate the max power (kcal/min) max capacity (kcal) O2 required for Anaerobic Glycolysis?
5-10 sec 16 (moderate power) 15 (moderate capacity) No trans. from rest to exercise during heavy exercise (60% VO2max) O2 insufficient of oxidative phosphorylation
What is: the time to max rate the max power (kcal/min) max capacity (kcal) O2 required for Oxidative Phosphorylation?
2-3 mins 10 (low power) 2000 (high capacity) Yes primary means of energy production
What does Phosphocreatine act as?
temporal (acts immediately) and spatial buffer (PCr and Cr can diffuse across the cell more rapidly than ATP and ADP, so they can bring phosphate groups from mitochondria to ATP)
What is anaerobic glycolysis?
Turns glucose (from blood and is transported via insulin or exercise) or glycogen (stored in m.) to pyruvate to lactate; results in 2 to 3 ATP
What does the reaction of pyruvate to lactate involve?
acidosis
generation of extra protons and decline in pH
What does the reaction of pyruvate to lactate involve?
acidosis
generation of extra protons and decline in pH (can change the function of enzymes)
What are potential substrates for oxidative phosphorylation? Which one is usually used
Lipid, carbs, or proteins + O2 > CO2 + H2O + 5 ATP
What is the rate of oxidative phosphorylation measured by?
VO2 = oxygen consumption = workload
Where does oxidative phosphorylation occur?
Inside the mitochondria
Generally describe the Tri-carboxylic Acid Cycle and ETC
Acetyl-Coa excretes CO2 and ATP and 4 e-
e- are transferred down the ETC until they get to O2 (terminal electron acceptor), form water, and the energy released powers the conversion of ADP to ATP
Generally describe the Tri-carboxylic Acid Cycle and ETC
Acetyl-Coa excretes CO2 and ATP and 4 e-
e- are transferred down the ETC until they get to O2 (terminal electron acceptor), form water, and the energy released powers the conversion of ADP to ATP
What is the lipid paradox?
We see lipid accumulation in m. is seen in old and sedentary (storage) as well as highly trained athletes (extra fuel)
What is the lipid paradox?
We see lipid accumulation in m. is seen in old and sedentary (storage) as well as highly trained athletes (extra fuel)
As intensity of the exercise increases, what substrate do we become less reliant and more reliant upon?
less reliant upon lipids
more reliant upon carbs
As duration of the exercise increases, what substrate do we become less reliant and more reliant upon?
less reliant on carbs
more reliant on lipids
What are the metabolic responses to high intensity, short duration activities? (anaerobic)
increase anaerobic substrates, (ATP, PCr, Creatine, Glycogen)
increased quantity and activity of key glycolytic enzymes (used in glycolysis)
What are the metabolic responses t mod intensity, long duration activities? (aerobic)
Metabolically: increase in number of mitochondria
increase in oxidation of fats at rest and submaximal exercise
(^fat mobilizing and metabolizing enzymes, lower catecholamine release, preserves glycogen stores to increase endurance)
increased ability to oxidize carbs at max exercise
(glycogen content)
What changes with aerobic training besides metabolic?
Cardiovascular
How does the cardiovascular system change with aerobic training?
^ left ventricular volume, ^ SV
lowered HR at rest and submaximal exercise
^ peripheral vasodilation capacity
How does ventilation change with aerobic training?
^ TV and RR at submaximal exercise
^ time for O2 diffusion into blood
lowered energy cost for breathing
