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)
Regulation of glycolysis in exercising muscle - what’s happening with phosphofructokinase activity
phosphofructokinase activity is increased by allosteric
regulators:
+ AMP
+ Pi
Where do we get AMP from? How do muscles make good use of ADP?
ADP + ADP = ATP + AMP
adenylate kinase (myokinase)
AMP can then and go and upregulate glycolysis to get things through glycolysis faster
Aerobic Generation of ATP by oxidation of glucose and fatty acids
• blood supplies fuels
• blood supplies O2
• active citric acid cycle
• electron transport chain oxidative phosphorylation
Why is the inner mitochondrial membrane less permeable the the outer in the mitochondria ?
Cos u don’t want protons to go across it
What’s carnitine up to?
- there is an enzyme in inner mitochondrial membrane which covalently attached the acryl chain to carnatine
- protein called carnotineacyltransfertase carrier and moves it into the matrix where another enzyme cleaves the FA and acetyl-carnatine and re-estifys the CoA to the FA chain for beta oxidation
- carnatine then pushed back out for reloading
We can make carnatine in our bodies and is in our diet
- therefore taking a supplement wont doing anything unless ur removing from heart surgery
Aerobic Generation of ATP by oxidation of glucose and fatty acids - marathon example
Balance of aerobic but save a little anarobic
- need to know how much anarobic u have to save for the last sprint dash
Aerobically trained rely less on glycogen “top up”
- dip into glycogen content later allowing you to go further
Glycogen keeps ya going for longer
Which is anarobic and which is aerobic ? Type 1 fibres and type 2 fibres
Type 2 is anaerobic
Muscle is specialised for the function
- develop correct muscle for training for the right excerise
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
Time course of training and detraining adaptations in mitochondrial density in skeletal muscle
Performance enhancing drugs
• EPO doping (erythropoietin increases red blood cell count – give you more O2)
– recombinant EPO
• Anabolic steroids (more muscle)
• Growth factors (more muscle)
– recombinant IGF-1, GH
Will gene therapy be appropriated?
- improving muscle content
The below transcription factors control the genes (upregulate transcription) for development of mitochondria
