C1 Ex Phys A Flashcards
energy
- what
- key roles (4)
- how much per day?
- energy is the ability to perform work
- comes from the breakdown of ATP
- key roles: 1. muscle contraction, 2. repair tissues, 3. nerve conduction, 4. hormone manufacturing
- typical person uses their own body weight + over in ATP per day
ATP
- role
- stored as?
- describe ATP splitting
- role of energy systems
- powers all metabolic reactions
- stored as glycogen or fat
ATP splitting
1. ATP molecule - 1 adenosine, 3 phosphates (Pi)
2. ADP molecule - 3rd Pi breaks off, releases energy, cause muscle contraction
3. ATP molecule - fuel used to resynthesise 3rd Pi to ADP
- ATP splitting/resynthesis must occur on an ongoing basis to generate constant energy
- this is the role of energy systems - breakdown fuel and use the energy to resynthesise ATP
creatine phosphate
- names
- storage
- sources
- usage
- known as: phosphocreatine, PC, CP, PCr
- storage: muscle + brain cells
- sources: half from food, half resynthesised by the body (in liver, kidneys, pancreas)
- usage: produces energy by splitting (used to regenerate ATP)
carbohydrates
- what
- transport
- storage (3)
- glycemic index
- includes sugars + starches, simple or complex
Transport: - broken down by digestive system into glucose
- transported in blood
- also, glucose is released from liver into blood to control blood glucose lvls
Storage: - in blood (GLUCOSE)
- in muscles + liver (GLYCOGEN)
- as fat (ADIPOSE TISSUE)
GLYCEMIC INDEX
- high GI - 70-100: quickly broken down, rapid energy release (jelly beans, sports drinks, fruit juice)
- medium GI - 55-70: (bread, couscous, sweet potato)
- low GI - 0-55: slow, sustained long term energy release (lentils, milk, carrots)
fats
-what
- made up of…
- transport
- storage
- sources
- why is it important? (6)
- high energy molecules
- made up of: triglycerides + fatty acids
- sources: food (oils, butter, avo, dairy, meat), and produced from storage of excess carbs
- transport: in blood as free fatty acids (FFAs)
Storage: - mostly as adipose tissue
- in muscles + liver (triglycerides)
- in blood (FFAs)
Important: - energy from fat breakdown mostly used during rest + periods of low int, sub max exercise
- produces most energy/gram than other fuels
- provides up to half of body’s everyday energy
- provides protection for organs
- production of cell membranes, hormones, cholestrol
- primary fuel source when carbs are depleted (long periods of exercise)
proteins
- made from…
- roles (4)
- usage
- transport
- storage
- made from AAs
Roles: - formation + growth of body tissues (esp muscles)
- repair + recovery of damaged tissues
- production of RBCs, hormones, enzymes
- emergency fuel source
- usage: event of extremity, after carbs/fats depleted (eg. ultra marathon, starvation)
- transport: in blood (AAs) to sites where needed
Storage: - not technically ‘stored’
- in blood/body fluids (AAs)
- in skeletal muscle (AAs)
- excess AAs converted to adipose tissue
hitting the wall
- occurs when liver + muscle glycogen stores are depleted
- fats must be used as primary energy source
- breakdown of fat is slow compared to carbs (requires more energy)
- ATP production is slowed
- results in sudden fatigue, decreased power output
- only occurs after extended period of exercise
glycogen sparing
- glycogen stores are not used early on in exercise due to body’s increased ability to use triglycerides as fuel
- aerobic system can metabolise fats efficiently, preserving glycogen stores for later
- this delays glycogen depletion, allowing athlete to access them at a later point
- = delayed exhaustion
ATP production during REST
(aerobic + fuel sources)
- energy requirement = low (not under physical stress)
- all energy supplied aerobically due to abundant O2 supply
- occurs in mitochondria
Fuel sources
- mostly fats (2/3), stored w/i muscle + body adipose tissue
- glucose/glycogen (1/3), breakdown in muscles + liver
- fat is richer source of energy, however requires abuandance of O2 to breakdown. therefore it is used at rest
ATP production during EXERCISE (anaerobic - why?)
- energy requirement = high
- body under physical stress = increased O2 demand to working muscles
- respiratory + circulatory systems unable to meet this
- body starts producing energy anaerobically
- if the activity is sub max, aerobic can be used
traits of anaerobic vs aerobic systems
Anaerobic
- provides energy quickly + powerfully in absence of O2
- only operate for short period
- small ATP yield
- produce toxic byproducts with cause fatigue
Aerobic
- produce ATP for sustained period of time (at rest or sub max)
- slow, sustained release, not rapid
- large ATP yield
- no toxic byproducts
Why are both anaerobic + aerobic systems necessary?
- aerobic = effecient at producing ATP (large yield, long period of time, sustained release)
- however, anaerobic is essential as O2 transportation is not efficient enough to sustain ATP production during higher int exercise
- limited speed by circ + resp systems
- CO2/O2 exchange is often not rapid enough to sustain the body’s ATP supplies
- need to be able to produce energy w/o O2!!!!
ATP-PC system
- when?
- system type
- fuel
- duration
- effectiveness
- When: power/explosive efforts (sprint, throw, weight lift, jump)
- anaerobic (no O2)
Fuel
- phosphocreatine (PC)
- stores located w/i muscle
- ATP produced through PC breakdown in muscle
- splitting of PC allows a phosphate to synthesise to an ADP molecule = ATP
- this occurs until PC stores are depleted
Duration
- two parts of the system
- ATP stores w/i muscle (0-2 sec)
- PC stores (2-10 sec)
- overall, ATP-PC system dominant for first 10 sec of max effort exercise
- takes 3-5 min to restore ATP/PC stores w/i muscles during rest
Effectiveness
- speed is fast: produces ATP almost instantly
- however: produces a limited quantity of ATP, depleted quickly
lactic acid system
- when?
- system type
- byproducts
- fuel
- duration
- process
- dominant during high int (still sub max) exercise (400m sprint, 500m row, team game)
- anaerobic (no O2)
- Fuel: glycogen/glucose, the incomplete breakdown of glucose (anaerobic glycolysis)
- Duration: dominant from 10-30 sec until 2-3 min of high int (after which aerobic takes over)
PROCESS
- glycogen (stored in liver + skeletal muscle)
- broken down to glucose
- converted via GLYCOLYSIS to
- pyruvic acid (small ATP yield)
when insufficent O2 (too much pyruvate for aerobic system to use), converted to
- = LACTIC ACID, H+ ions
lactic acid accumulation
- lactic acid is produced by body constantly
- during rest + most exercise (not max), lactic acid production = the rate at which it is removed
- = no accumulation
AT HIGH INT:
- lactic acid & H+ ion production increases, rate of removal increases
- athlete will reach their lactate threshold
- if continued, LA + H continue to increase expotentially
- increase in muscle acidity, fatigue,
- cannot physically continue, must slow or stop
lactate threshold/lactate inflection point (LIP)
- graphs
- the point at which the production of lactate is greater than the rate of its removal
- once reached, LA + H increase expotentially
- also referred to as OBLA
lactic acid removal
- determined by?
- fates of LA
- rate of removal (muscle to blood stream) determined by rate of blood flow thru muscles)
FATES
- a little taken up by heart + skeletal muscle, converted to pyruvic acid, used for ATP
- MAJORITY converted by the liver to:
- 65% resynthesised to CO2 + H2O
- 20-25% to glycogen
- 10% to protein
- 5% to glucose
aerobic system
- when?
Location, fuel, process, byproducts, yield:
- glycolysis
- citric acid cycle
- electron transport chain
- dominant during sub-max efforts from 2-5 min onwards
- most efficient system, produces most ATP overall
- slow ATP production, large yield
- CO2, H2O + heat byproducts
GLYCOLYSIS
- occurs in muscle cell
- glycogen -> glucose -> pyruvic acid
- anaerobic breakdown of glycogen/glucose
- occurs in both aerobic + anaerobic systems (in LA system, P is converted to lactate instead)
- only needed when carbs are used as the fuel source (fats + proteins go straight to next stage)
CITRIC ACID CYCLE
- occurs in mitochondria
- fuel: pyruvic acid / fats (lipolysis) /prtoteins
- aerobic, fuel combines with O2
- byproducts: CO2 (released via lungs), H+ ions (used in next stage)
- ATP yield: small
ELECTRON TRANSPORT CHAIN
- occurs in mitochondria
- byproducts: H2O (diffuses into tissues/blood), heat (released)
- aerobic
- ATP yield: LARGE (majority)