Lecture 36: Exercise

Question 1

What is the difference between anaerobic and aerobic exercise?
- Anaerobic exercise

Answer 1

• high intensity + rapid generation of energy + short periods
  e. g sprinting and weightlifting
• anaerobic exercise dones NOT require O2
• phoshocreatine + glycogen

Question 2

What is the role of phosphocreatine as an energy store in muscle?

Answer 2

• is an “on site”, “fast fuel”
• Is a high energy phosphate compound
• Phosphate can be transferred to ADP to make ATP

Question 3

What is glycogen?

How is glycogen mobilised to glycogen phoshphorylase?
- what are the steps involved

How does this provided fuel for anaerobic glycolysis in exercising muscle?

Answer 3

• is an ‘on site’ store of glucose in muscle
• is mobilised to glucose 1-phosphate by glycogen phosphorylase
• glucose 1-phosphate is converted to glucose 6-phosphate
• glucose 6-phosphate is the fuel for anaerobic glycolysis

Question 4

What are the adaptions of different muscle types that make them suitable for different types of exercise?

Answer 4

Anaerobic = mainly type II fibres
Aerobic = mainly type I fibres
Muscle adaptions to endurance training
- selectively hypertrophy of Type I (aerobic) fibres
- Increased number of blood capillaries per muscle fibre
- Increased myoglobin content
=-Increases size and number of mitochondria; increases cristae
- Increased capacity of mitochondria to generating ATP by oxidative phosphorylation
- Increases capacity to oxidise to lipid and carbohydrate

Question 5

Identify the fuels and metabolic pathways used to supply ATP for various types of exercise

Answer 5

Muscle = resting - mostly fatty acids

marathon - mix of fatty acids and glucose

Question 6

What is the difference between anaerobic and aerobic exercise?
- Aerobic exercise

Answer 6

• low intensity + prolonged, sustained running
  e. g swimming and walking
• requires O2
• oxidation of glucose and fatty acids

Question 7

What is anaerobic glycolysis ?

How does mobilising glycogen provide fuel for anaerobic glycolysis in mucsle?

Answer 7

• muscle glycogen is a source of fuel
• O2 not required
• ATP generated by SLP
• pyruvate reduced to lactate to regenerate NAD+
• ATP generation very rapid but for a short time only
• Lactate can cause muscle pH to drop thus fatigue

Question 8

How is glycolysis regulated in exercising muscle?

Answer 8

• glycogen mobilisation is stimulated by Ca2+ and adrenaline

- Phosphofructokinase activity is increased by allosteric regulators = +AMP, + Pi