CH3: Bioenergetics of Exercise and Training Flashcards
Energy demands placed on the body by a particular exercise
metabolic specificity
Flow of energy in a biological system
bioenergetics
Catabolism
breakdown of large molecules into smaller molecules to release energy
Anabolism
synthesis of larger molecules from smaller molecules using energy from catabolic reactions
Energy releasing reactions
exergonic
Energy requiring reactions
endergonic
Catabolic reactions tend to be exergonic or endergonic?
exergonic
The contraction of muscle is exergonic or endergonic?
endergonic
The total of all catabolic (exergonic) and anabolic (endergonic) reactions in a biological system
metabolism
what allows the transfer of energy from exergonic to endergonic reactions in the body?
ATP (adenosine triphosphate)
hydrolysis (with regard to bioenergetics)
breakdown of one ATP molecule to yield energy
what enzyme catalyzes the hydrolysis of ATP?
adenosine trisphosphatase (ATPase)
what are the three types of ATPase in the body and what do they do?
myosin (crossbridge recycling)
calcium (pumping calcium into the sarcopolasmic reticulum)
sodium-potassium (maintaining sarcolemmal concentration gradient after depolarization)
where to ATP producing processes occur?
in the cell
what are the three basic energy system in mammalian muscle cells? (used to replenish ATP)
phosphagen, glycolysis, oxidative
processes that do not require oxygen are referred to as?
anaerobic
processes that require oxygen are referred to as?
aerobic
List the two anaerobic mechanisms covered and where they occur
phosphagen and glycolytic systems, sarcoplasm of a muscle cell
List two mechanisms within the oxidative system and where they occur
krebs cycle and electron transport, mitochondria of a muscle cell
what macronutrient can be metabolized for energy without the direct involvement of oxygen?
carbohydrates
the phosphagen system is active at the start of all exercises regardless of intensity (T/F)
T
what does the phosphagen system rely on?
the hydrolysis of ATP and the breakdown of creatine phosphate
how does the body maintain the concentration of ATP needed to perform exercise?
the creatine kinase reaction
what is the ration of CP and ATP concentration found under normal circumstances?
4:1 - 6:1
what muscle fiber types contain the highest concentration of CP?
Type II
What product of the adenylate kynase reaction is a powerful stimulant for glycolysis?
AMP
what law states that the concentrations of reactants or products in a solution will drive the direction of the reactions?
law of mass action
what is glycolysis?
the breakdown of carbohydrate
what are the two sources of carbohydrates in glycolysis?
glycogen in the muscle and glucose in the blood
what is the end product of glycolysis?
pyruvate
the end result of glycolysis may proceed in which two directions?
- pyruvate to lactate in sarcoplasm
2. pyruvate to the mitochondria
what is fast glycolysis and why is it called that?
pyruvate to lactate, because ATP resynthesis occurs at a faster rate than krebs cycle ATP resynthesis
what controls the conversion of pyruvate (determines its fate)
the energy demands of the cell
high intensity and quick = convert to lactate
low intensity and oxygen is present = krebs cycle
the end result of the catylization of pyruvate by lactate dehydrogenase is what?
Lactate (NOT lactic acid)
concentration of lactate in muscular tissue causes fatigue (T/F)
F
what is responsible for peripheral fatigue that occurs during exercise?
reduction in PH (metabolic acidosis)
what is lactate used as especially in type I and cardiac muscle fibers?
an energy substrate
what is glucogenesis?
the formation of glucose from non carbohydrate sources
how is lactate cleared and buffered from the blood?
through oxidation within the muscle fiber where it was produced, or transported in the blood to other muscle fibers to be oxidized
when lactate is transported to the liver what does it become and what is this process called?
glucose, the cori cycle
what gets transported alongside pyruvate to the mitochondria?
NADH
what is the difference between substrate-level and oxidative phosphorylation?
substrate level is the direct resynthesis of ATP from ADP
oxidative level resynthesizes ATP in the electron transport chain
what is glycogeneolysis
when muscle glycogen is broken down to glucose
what are the two sources of glucose for the hydrolysis of ATP?
blood glucose and muscle glycogen
what is the net resynthesis of ATP when glycolysis begins from muscle glycogen?
3
what is the net resynthesis of ATP when glycolysis begins from blood glucose?
2
what enzyme catalyzes the reaction that converts fructose-6-phosphate to fructose-1, 6-biphosphate?
PFK (phosphofructokinase)
allosteric inhibition
when an end product binds to the regulatory enzyme and decreases its turnover rate, slowing product formation
allosteric activation
when an “activator” binds with the enzyme and increases its turnover rate, speeding up product formation
the term given to the slowest step in the overall reaction
rate limiting step
what is the rate limiting step in glycolysis?
PFK (phosphofructokinase)
there is an increased reliance on what once the lactate threshold is overcome?
anaerobic mechanisms for energy production
when does the LT (lactate threshold) typically begin in untrained vs trained individuals?
50-60% of oxygen uptake (untrained)
70-80% of oxygen uptake (trained)
at what concentration of lactate does the onset of blood lactate accumulation occur?
4mmol/L
during prolonged, submaximal, steady state work what is the shift in macronutrient used for energy?
from almost 100% carbohydrates to fats and to a much smaller extent protein
what two types of molecules transport hydrogen ions to the ETC to product ATP from ADP?
NADH and FADH
cytochromes
series of electron carriers in a chain
what percent of ATP supply comes from oxidative phosphorylation, substrate-level phosphorylation?
90%, 10%
what happens to free fatty acids when they enter the mitochondria?
they undergo beta oxidation
what are the end products of beta oxidation and where are they transported to?
hydrogen protons (transported by NADH and FADH to the ETC) and acetyle-CoA (enters the krebs cycle directly)
which macronutrient has the greatest capacity for ATP synthesis on the molecular level?
fats
what major amino acids are oxidized in skeletal muscle?
branched chain amino acids (leucine, isoleucine, valine)
how much energy (a range) does the oxidation of protein contribute during prolonged activity?
3-18%
what is the relationship between rate of ATP production and capacity to produce ATP for any given system?
inverse
what does the extent to which a given energy system contributes to ATP production depend on primarily?
the intensity of the activity (duration being secondary)
at rest only the oxidative system is used for energy (T/F)
F - never is any one system used for total energy
approximately how much glycogen is stored in the bodys total muscle? how much in the liver
300-400g in muscle, 70-100g in liver
muscle glycogen is used primarily during high intensity exercise (T/F)
T
at what blood glucose value do hypoglycemic reaction begin to occur?
2.5mmol/L
two resistance training sessions of equal work but differing intensities will deplete the same amount of glycogen (T/F)
T
oxygen deficit
the initial anaerobic contribution to energy at the start of exercise to compensate for the slow start of the aerobic system
oxygen debt
post exercise oxygen uptake which remains higher then pre exercise levels for a period of time
what is the name for the oxygen uptake above resting values used to restore the body to the preexercise condition?
EPOC (excess poste-exercise oxygen consumption)
brief repeated bouts of high intensity exercise with intermittent recovery periods?
HIIT
predetermined intervals of exercise and rest periods
interval training
cross training
combination of anaerobic and aerobic activity
aerobic training enhances anaerobic training goals (strength, power) (T/F)
F
