9-25c Metabolic Pathways for Aerobic Exercise

Question 1

What chemical pathways does m. use to regenerate ATP?

Answer 1

glycolysis > pyruvate or lactate
creatine shuffle
oxidative phosphorylation > ETC > Krebs Cycle

Question 2

Describe the fuel sources used to drive energy pathways

Answer 2

e

Question 3

Describe the energy pathways employed at rest and during exercise?

Answer 3

e

Question 4

Describe the metabolic adaptations to training

Answer 4

e

Question 5

What are the key characteristics to each of the chemical pathways?

Answer 5

e

Question 6

What fuel sources are available to power oxidative phosphorylation? When are they most utilized?

Answer 6

Lipids: at rest
glucose & glycogen (carbohydrates): heavy exercise
protein: disease states and starvation

Question 7

How do the different fuel sources compare?

Answer 7

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

Question 8

How does ATP concentration remain the same?

Answer 8

ATP is regenerated just as quickly to maintain homeostasis

Question 9

What is:
the time to max rate
the max power (kcal/min)
max capacity (kcal)
O2 required 
for Phosphocreatine?

Answer 9

fast (immediate)
High power (36)
low (11)
No

Question 10

What is:
the time to max rate
the max power (kcal/min)
max capacity (kcal)
O2 required 
for Anaerobic Glycolysis?

Answer 10

5-10 sec
16 (moderate)
15 (moderate)
No

Question 11

What is:
the time to max rate
the max power (kcal/min)
max capacity (kcal)
O2 required 
for Oxidative Phosphorylation?

Answer 11

2-3 mins
10 (low)
2000 (high)
Yes

Question 12

What is:
the time to max rate
the max power (kcal/min)
max capacity (kcal)
O2 required 
for Oxidative Phosphorylation?

Answer 12

2-3 mins
10 (low)
2000 (high)
Yes

Question 13

What is the phosphocreatine reaction?

Answer 13

ADP + PCr + H+ >creatine kinase> ATP + Cr

Question 14

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?

Answer 14

fast (immediate)
High power (36)
low capacity (11)
No
Short term but high power 
trans. from rest to exercise

Question 15

What is:
the time to max rate
the max power (kcal/min)
max capacity (kcal)
O2 required 
for Anaerobic Glycolysis?

Answer 15

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

Question 16

What is:
the time to max rate
the max power (kcal/min)
max capacity (kcal)
O2 required 
for Oxidative Phosphorylation?

Answer 16

2-3 mins
10 (low power)
2000 (high capacity)
Yes
primary means of energy production

Question 17

What does Phosphocreatine act as?

Answer 17

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)

Question 18

What is anaerobic glycolysis?

Answer 18

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

Question 19

What does the reaction of pyruvate to lactate involve?

Answer 19

acidosis

generation of extra protons and decline in pH

Question 20

What does the reaction of pyruvate to lactate involve?

Answer 20

acidosis

generation of extra protons and decline in pH (can change the function of enzymes)

Question 21

What are potential substrates for oxidative phosphorylation? Which one is usually used

Answer 21

Lipid, carbs, or proteins + O2 > CO2 + H2O + 5 ATP

Question 22

What is the rate of oxidative phosphorylation measured by?

Answer 22

VO2 = oxygen consumption = workload

Question 23

Where does oxidative phosphorylation occur?

Answer 23

Inside the mitochondria

Question 24

Generally describe the Tri-carboxylic Acid Cycle and ETC

Answer 24

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

Question 25

Generally describe the Tri-carboxylic Acid Cycle and ETC

Answer 25

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

Question 26

What is the lipid paradox?

Answer 26

We see lipid accumulation in m. is seen in old and sedentary (storage) as well as highly trained athletes (extra fuel)

Question 27

What is the lipid paradox?

Answer 27

We see lipid accumulation in m. is seen in old and sedentary (storage) as well as highly trained athletes (extra fuel)

Question 28

As intensity of the exercise increases, what substrate do we become less reliant and more reliant upon?

Answer 28

less reliant upon lipids

more reliant upon carbs

Question 29

As duration of the exercise increases, what substrate do we become less reliant and more reliant upon?

Answer 29

less reliant on carbs

more reliant on lipids

Question 30

What are the metabolic responses to high intensity, short duration activities? (anaerobic)

Answer 30

increase anaerobic substrates, (ATP, PCr, Creatine, Glycogen)
increased quantity and activity of key glycolytic enzymes (used in glycolysis)

Question 31

What are the metabolic responses t mod intensity, long duration activities? (aerobic)

Answer 31

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)

Question 32

What changes with aerobic training besides metabolic?

Answer 32

Cardiovascular

Question 33

How does the cardiovascular system change with aerobic training?

Answer 33

^ left ventricular volume, ^ SV
lowered HR at rest and submaximal exercise
^ peripheral vasodilation capacity

Question 34

How does ventilation change with aerobic training?

Answer 34

^ TV and RR at submaximal exercise
^ time for O2 diffusion into blood
lowered energy cost for breathing