37 Flashcards
Only enough ATP for 1 second
Characteristics of anaerobic exercise and examples
• high intensity
• rapid generation of force
• short periods
• examples
- sprinting
- weight-lifting
Characteristics of aerobic exercise and examples
• low intensity
• prolonged, sustained exercise
e.g.
- long-distance running
- swimming
- walking
Approximate contribution of aerobic and anaerobic energy sources to total energy production in events of different durations involving maximal work
Longer = more aerobic and less anaerobic %
Shorter = less aerobic and more anaerobic %
The longer you exercise the more aerobic it must be
The longer you exercise the more ______ it must be
The longer you exercise the more aerobic it must be
What ways has muscle of regenerating ATP from ADP?
Anaerobic exercise: Does not require O2
• phosphocreatine
• glycogen
Aerobic exercise: Requires O2
• oxidation of glucose and fatty acids
(Oxidative phosphorylation to get ATP needs O2 as the terminal acceptor)
Phosphocreatine features
• is “on site”, “fast fuel”
• 20 µmol per g muscle
• is a ‘high-energy phosphate’ compound (there is a bond
that can be hydrolysed to make ATP)
• phosphate can be transferred to ADP to make ATP
Made from Gly, Arg and Met (in liver but transferred to muscle)
20 µmol/g — lasts ~10 s
- Energy buffering system
- creative can be converted back if ATP is available
- excess creative is excreted in urine (can test if kidneys are \
functioning)
Creatine
- there is a relationship between how much creative is in your muscles and how long you can stay on a bicycle
- but nothing to do with long distance running
Glycogen - features of how it is a fuel in anaerobic exersie
• 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
How glycolysis is activated via adrenaline on muscle cell
- Adrenaline binds to beta adrenergic receptors on muscle cells
- when the hormone binds, a protein is bound to the receptor (GTP binds to the receptor) and there is a conformational change that releases the protein
- this protein then interacts with membrane bound adenlyte cyclase which will convert ATP into cAMP
- the GTP attached to the protein is hydrolysed back to GDP and will detach from the adenlyte cyclase
- if the hormone is still bound to the receptor, the protein can reaccociate with the receptor and bind another GTP, and reaccocaite with adencyclease again and make more cAMP
- will build up cAMP as long as the adrenaline is bound the the receptor
- the cAMP activates a kinase which phosphrilayes another kinase etc, then glycogen phosphrilayse is activated and will cleave off a glucose from glycogen
Adrenaline binds to beta adrenergic receptors on muscle cells which stimulates…
the mobilisation of glycogen to provide fuel for glycolysis
- lactate is acidic, it builds up and the you get fatigue and the acidic it’s interrupts muscle contraction and slows down the key enzyme in the glycosidic pathway - phosphofukatkinisase
Anaerobic Glycolysis features
• muscle glycogen source of fuel
• O 2 not required
• ATP generated by substrate-level-phosphorylation
• pyruvate reduced to lactate to regenerate NAD+
• ATP generation very rapid but for short time only
• lactate can cause muscle pH to drop, thus fatigue
What is glycogen mobilisation stimulated by in excercising muscle?
by Ca++ and adrenaline (stress hormone)
(Calcium also helps with contraction)