KIN 210 - Midterm

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

1. FFA's in blood attached to albumin (from white adipose tissue)

2. 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

1. form body structures and enzymes

2. fuel source

3. 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

1. adipose tissue (triglyceide)

2. blood-plasma (glycerol, FFA w albumin)

3. muscle (intramuscular triglyceride and muscle glycogen)

4. blood-plasma (glucose)

key metabolic regulators of aerobic ATP production

1. energy state of cell (ADP/ATP)

2. Redox state of cell (NAD/NADH)

3. Intracellular Ca 2+.

4. 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:

1. depletion of something imp. OR

2. 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

Muscle La: T1/2 and Full recovery times

12-20 min; <60 min. active recovery

Blood La: T1/2 and Full recovery times

15-25 min; 60+ min. active recovery

Muscle Glycogen: T1/2 and Full recovery times

5-6 hrs; 1-2 days. Nutrition, hydration, control of further exercise key in recovery.

how training improves the ability to recover

increased: enzymes, capillarization, oxidative capacity, buffering capacity, sensitivity of central and peripheral physiological mechanisms.

the same exercise bout now constitutes less of perturbation.

ATP-PC work interval

1-10s

ATP-PC W:R ratio

1:3-1:20

Glycolysis work interval

10-90s

Glycolysis W:R ratio

1:2-1:5 (stress pH buffering capacity of muscle)

Aerobic work interval

>90s

Aerobic W:R ratio

1:1/2 - 1:3 (to maintain high HR, oxidative metabolism)

Total Energy Expenditure

"useful" work done + heat produced ("wasted" energy)

1st Law of Thermodynamics

energy will neither be created nor destroyed

2nd Law of Thermodynamics

will release energy as heat

basic unit of heat

calorie

calorie

amount of heat to raise 1g of water 1 degree Celsius.

1 Calorie = 1000 calories = 1 kcal.

1 kcal = 4186 J

Indirect Calorimetry: Open Circuit Spirometry

uses changes in ventilation (O2 consumption and CO2 production) to estimate # kcal used for activity