Aerobic vs. Anaerobic Glucose Metabolism

Question 1

What are fuels for muscle?

Answer 1

-ATP
-glucose
-glycogen
-triacylglycerol/ fatty acids
-proteins/ amino acids
-phosphocreatine

Question 2

What is phosphocreatine?

Answer 2

-= creatine phospahte
-primarily in skeletal muscle
-some in heart and brain
-provides “reservoir” of ATP
-catalyzed by creatine kinase
Phosphocreatine + ADP <-> creatine + ATP

Question 3

What are the 2 sources of energy for muscle contraction?
What is the additional one?

Answer 3

-phosphocreatine
-anaerobic metabolism:
primarily glycogen from glycogenolysis or glycolysis
glycogen forms 3 ATP and glucose forms 2
-aerobic metabolism:
glycogen, fatty acids (also glucose, amino acids, ketone bodies), produces much more ATP than does anaerobic metabolism (30-32 ATP per mol of glucose, more than 100 per mol of fatty acids), limited by oxygen supply

Question 4

What is the ATP yield from anaerobic glycolysis?

Answer 4

glycogen forms 3 ATP and glucose forms 2

Question 5

What is the ATP yield from aerobic oxidation of glucose?

Answer 5

30-32 ATPs per glucose

Question 6

What is the bottom line? (2 effects)

Answer 6

Glucose has to go much faster in the absence of oxygen to supply same amount of ATP
Pasteur effect: oxygen inhibits fermnation
warburg effect: most cancers have high rate of glucose metabolism

Question 7

What are limits to oxygen supply?

Answer 7

-blood flow
-capillaries
-oxygen uptake in the alveoli
-oxygen concentration
-number of erythrocytes (red blood cells)

Question 8

Aerobic vs. Anaerobic metabolism endurance vs sprint:

Answer 8

Marathon run: most aerobic
Sprint: mostly anaerobic

Red muscle: aerobic
White muscle: anaerobic

Question 9

What happens when sprinting?

Answer 9

-lactate can reach 20 mM
-converted to glucose (Cori cycle)
-build up oxygen debt

Question 10

What happens when sprinting?

Answer 10

-lactate can reach 20 mM
-converted to glucose (Cori cycle)
-build up oxygen debt

Question 11

What is the lactic acid myth?

Answer 11

-cells produce lactate ions not lactic acid, this increases pH

Question 12

What lowers pH during anaerobic exercise?

Answer 12

-hydrolysis of cytoplasmic ATP produced protons
-mitochondria use protons to maintain the proton concentration, so no protons released from mitochondrial ATP hydrolysis
-high dependence on cytoplasmic ATP will lower pH

Question 13

Go owe fuel use in notes

Answer 13

done

Question 14

What are the fates of aerobic and anaerobic metabolism in muscle?

Answer 14

Glycogen -> pyruvate-> splits into two paths
1. Anaerobic: lactate( (little ATP, not limited by oxygen)
2. Aerobic (Krebs, oxidative phosphorylation): CO2 plus water (lots of ATP, limited by oxygen)

Question 15

Explain the 2 types of muscle fibers.

Answer 15

Type I:
-slow twitch (dark)
-specialized for prolonged, slow effort
-many mitochondria
-high myoglobin content
-lower glycolytic capacity
-high fat
Type II:
-fast twitch (white)
-specialized for short bursts of activity
-few mitochondria
-low myoglobin
-high glycolytic capacity
-low fat
-type II a and II b

Question 16

Explain the 2 types of muscle fibers.

Answer 16

Type I:
-slow twitch (dark)
-specialized for prolonged, slow effort
-many mitochondria
-high myoglobin content
-lower glycolytic capacity
-high fat
Type II:
-fast twitch (white)
-specialized for short bursts of activity
-few mitochondria
-low myoglobin
-high glycolytic capacity
-low fat
-type II a and II b

Question 17

How does PET scan work?

Answer 17

-detects pairs of gamma-rays emitted indirectly by a position-emitting radionuclide
-2-deoxyglucose taken up and phosphorylated, not further metabolized
-18F-labeled 2 deoxyglucose (FdG) taken up by many tumors