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energy
capacity to perform work (J)
energy transfer
production of ATP
adenosine
adenine + di-ribose
ATP
adenine + di-ribose + inorganic phosphate groups
acetyl Co-A
crossroad of pathways in metabolism. breakdown of all macros reach this point
cellular respiration
the process whereby cells transfer energy from food to ATP in a stepwise series of reactions - requires oxygen (AEROBIC).
C6H12O6 + 6O2 --> 6CO2 + 6H2O + energy
kinetic energy
energy of motion
metabolism
all of the energy transformations (production of ATP) that occur in the human body; allows work to be done.
exergonic reactions
chemical processes that release energy (downhill)
endergonic reactions
chemical processes that store or absorb energy (uphill). requires energy.
reduction
gain of e- or H+
oxidation
loss of e- or H+
bioenergetics
the study of the transformation of energy in living organisms
where enzymes (proteins) are made in the cell
all proteins come from DNA (coded for)...so in nuclei first then ribosomes (where proteins are produced)
enzymes
highly specific reusable biological protein catalysts "-ase". reduce the activation energy required for biologic rxns.
rate limiting (regulatory) enzymes
"bottleneck" - analogous to traffic lights. affect rate of entire pathway.
active site
where substrate binds with enzyme. where reaction actually occurs. highly specific (particular shape)
cofactors
"helper molecules". help to make an enzyme functional. coenzymes = complex ORGANIC molecules required by some enzymes to carry out catalysis. often intermediate carriers of e-, specific atoms or functional groups transferred in the overall rxn.
primary energy sources for the resynthesis of ATP for muscular work
PCr, glucose/glycogen, fats, protein
ATP-PCr system
High power, low capacity. occurs in the sarcoplasm of the muscle fibre (cell).
where Creatine comes from
made in the liver or ingested (meat products). >95% stored in skeletal muscle
effect of creatine supplementation
increases Cr levels in muscle cells...thus increases PCr levels for faster recovery and ATP restoration. can exert energy MORE OFTEN. less lactate is produced.
Cr supplementation responders
vegetarians/ vegans. posses high FT fibres
Cr supplementation non-responders
have high dietary protein intake, already have high endogenous stores of Cr and PCr, have mostly ST fibres
glycogenolysis
the process by which stored glycogen (in liver & skeletal muscle) is broken down (hydrolyzed) to provide glucose
glycolysis
the energy pathway responsible for the initial catabolism of glucose that begins with glucose or glycogen and ends with the production of pyruvate (aerobic slow) or lactate (anaerobic fast)
glycogenesis
the production of glycogen in muscle and liver (by glycogen synthase)
gluconeogenesis
the creation of glucose (in the liver) from non CHO sources: glycerol, lactate/ pyruvate (Cori Cycle), alanine (amino acid)
glucagon
a hormone formed in the pancreas that promotes the breakdown of glycogen to glucose in the liver. released in response to low b.gluc. (raises b.gluc)
insulin
a hormone formed in the pancreas that allows glucose to be absorbed from the b.stream (permits cells to use glucose for energy). released in response to high b.gluc. (lowers b.gluc)
GLUT 1 transporters
transport glucose from blood into muscle cell in normal conditions
GLUT 4 transporters
transport glucose from blood into muscle cell after eating or during exercise. signalled by insulin or Ca 2+. in addition to GLUT 1 transporters. get more glucose into muscle more quickly!
product of fast glycolysis
lactate
product of slow glycolysis
pyruvate
Glycolytic/ Anaerobic Lactic system
lower power, higher capacity than ATP-PCr system. many steps. occurs in sarcoplasm
LDH 1
cardiac muscle form of LDH
LDH 5
skeletal muscle form of LDH
rate of glycolysis/ glycogenolysis is influenced by
NAD+/ NADH ratio; ADP/ATP ratio; substrate availability
lactate clearance
oxidation, gluconeogenesis, transamination, sweat/urine
lactate production
muscle contraction, enzyme activity, FT fibres, sympathetic neurohormonal activation, insufficient oxygen
MCT 1
transports lactate into mitochondria (intracellular La shuttle). converted back to pyruvate.
MCT 4
transports lactate out of the muscle cell (extracellular La shuttle). liver gluconeogenesis, skin excretion, heart oxidation.
Cori Cycle
gluconeogenesis. formation of glucose from lactate/ pyruvate in the liver.
H+ buffers
HCO3, inorganic phosphates, proteins (histidine & Hb). maintains pH and extends anaerobic power production
HCO3 supplementation
supplementation for anaerobic lactic system. increases blood pH. increases rate of H+ efflux due to increased gradient...increases buffering potential, therefore improved anaerobic performance
B-alanine supplementation
supplementation for anaerobic lactic system. B-alanine + L-histidine --> carnosine. important intramuscular buffer.
factors that affect the rate of enzymic rxns
pH, temp, conc of the enzyme, conc of the substrate, presence of cofactors
where mATPase lies within the muscle fibers
myosin filament on the cross bridges. allows cycling of the cross bridges
macronutrients that are the major sources of energy for the body
CHO and fats
what the energy from food does
rephosphorylates ADP to ATP
major components of the aerobic pathway
aerobic glycolysis, krebs citric acid cycle, beta (fat) oxidation, electron transport chain
NADH + H+ and FADH2
shuttle energy around the cell: dump into e- transport chain
malate-aspartate shuttle
shuttles NADH from glycolysis into the mitochondria in the heart
glycerol phosphate shuttle
shuttles NADH from glycolysis into the mitochondria in muscle
free radicals
electrons that leak from ETC prematurely to O2. cause degradation. antioxidants prevent them.
Exercise Fat Metabolism Sources
FFA's in blood attached to albumin (from white adipose tissue)
Stored triglyceride in muscle
albumin
blood protein. carrier for free fatty acids (freed from glycerol), transport in the b.stream.
where fat is stored
white adipose tissue and ST muscle fibre
carnitine shuttle system
shuttle system that moves Fatty acyl CoA into the mitochondria (and burned through aerobic metabolism). *for complex, long fatty acids (smaller can diffuse in)
ketosis
increase fat, decrease CHO in diet. oxaloacetate decreases because used for GNG. ultra endurance sport interest.
amino acid functions
form body structures and enzymes
fuel source
gluconeogenic precursors (ex. alanine)
*cannot be stored. excreted as urea (urine/sweat)
transamination
transformation of an amino group (nitrogen) to a ketoacid to form a new amino acid. most common amino acid formed is glutamate.
oxidative deamination
removal of an amino group (nitrogen) completely to produce a keto acid (Krebs intermediate), NADH (to ETC) and NH3 (toxic --> excreted). less common than transamination.
4 main stores of CHO and fats
adipose tissue (triglyceide)
blood-plasma (glycerol, FFA w albumin)
muscle (intramuscular triglyceride and muscle glycogen)
blood-plasma (glucose)
key metabolic regulators of aerobic ATP production
energy state of cell (ADP/ATP)
Redox state of cell (NAD/NADH)
Intracellular Ca 2+.
trigger enzymes
myoglobin
simpler version of Hb. local oxygen store in muscle.
subsarcolemmal mitochondria
mitochondria that increase in size and number with long duration endurance training
intermyofibrillar mitochondria
mitochondria that increase in size and number with high intensity aerobic interval training.
metabolic conditioning
high intensity interval training designed to challenge all systems
fatigue
loss of capacity for developing force and/or velocity of muscle...resulting from muscle activity under load..reversible by rest. caused by:
depletion of something imp. OR
accumulation of something detrimental
possible sites of fatigue
central nervous system, peripheral nervous system, skeletal muscle fibres
heat accumulation
source of fatigue that inhibits enzyme function
free radical accumulation
contracting skeletal muscle produces reactive oxygen and nitrogen species that can cause damage to proteins & lipids and result in contractile dysfunction & fatigue. important mechanism of aging.
impaired oxygen delivery causes
high intensity aerobic exercise, pollution or altitude
results of impaired oxygen delivery
"desaturation" of Hb. decreased aerobic metabolism --> increased reliance on anaerobic metabolism --> increased H+ --> increased fatigue.
CHO mouth rinsing
oral CHO receptors directly signal to brain areas linked to motivation and reward (pleasure receptors). can increase high intensity exercise performance.
factors that influence fatigue
environment, hydration, nutrition, trained state, muscle fibre type, equip/tech/clothing, efficiency/technique, psychological factors
recovery
the physiological processes that return an individual to or toward a resting state
EPOC (Recovery VO2)
Excess Post-Exercise Oxygen Consumption. higher than normal O2 consumption. the O2 requirement of metabolism during recovery from exercise (usually > O2 deficit....oxygen debt gets more than repaid)
O2 Deficit
period of time at the start of exercise during which aerobic metabolism is adjusting to meet metabolic demands
Exercise VO2
O2 requirement of metabolism for the exercise bout
ATP-PC stores: T1/2 and Full recovery times
20-30s; 2-8 min. passive recovery
Muscle H+: T1/2 and Full recovery times
5-8 min; 12-20 min active recovery
Blood H+: T1/2 and Full recovery times
10-20 min; 30-60 min. Active recovery