Metabolism - Lecture Thirty-Seven Flashcards
Fuel Storage
Anaerobic exercise
High intensity
Rapid generation of force
Short period
e.g. sprinting and weight-lifting
Aerobic exercise
Low intensity
Prolonged, sustained exercise
e.g. long-distance running, swimming and walking
What ways has muscle of regenerating ATP from ADP: anaerobic exercise?
Phosphocreatine
Glycogen
What ways has muscle of regenerating ATP from ADP: aerobic exercise?
Oxidation of glucose and fatty acids
Phosphocreatine
is ‘on site,’ ‘fast fuel.’ There’s about 20 mol per g of muscle and is a high energy phosphate compound
Phosphate
Can be transferred to ADP to make ATP
Glycogen
is an ‘on-site’ store of glucose in muscle and is mobilised to glucose 1-phosphate by glycogen phosphorylase
Glucose 1-phosphate is converted to
Glucose 6-phosphate
Glucose 6-phosphate
Fuel for anaerobic glycolysis
Adrenaline binds to beta adrenergic receptors on muscle cells
The hormone comes in and binds as an agonist to the receptor in the cell membrane stimulating the mobilisation of glycogen to provide fuel for glycolysis
If the g protein coupled receptor has a GDP
It will associate with the receptor AND hormone
GTP
Will associate with Adenylase cyclase which makes cAMP from ATP
Anaerobic Glycolysis
Muscle glycogen source of fuel. ATP is generated by substrate-level-phosphorylation
Anaerobic Glycolysis: Pyruvate reduced to?
Lactate to regenerate NAD+
ATP generation
Very rapid but for a short time only
Lactate can cause
Muscle pH to drop, therefore causing fatigue
What is glycogen mobilisation stimulated by?
Ca++ and adrenaline (stress hormone)
How is phosphofructokinase activity increased?
By allosteric regulators; AMP and Pi
Muscle adaptations to endurance training
Selective hypertrophy of Type I (aerobic) fibres
Increased number of blood capillaries per muscle fibre
Increased myoglobin content
Increased size and number of mitochondria; increased cristae
Increased capacity of mitochondria to generate ATP by oxidative phosphorylation
Increased capacity to oxidise lipid and carbohydrate
Performance enhancing drugs
EPO doping - recombinant EPO
Anabolic steroids
Growth factors - recombinant IGF-1, GH
