Chp 3 Bioenergetics of Exercise and Training Flashcards
hydrolysis
the breakdown of one molecule of ATP to yield energy
myosin APTase
enzyme that catalyzes ATP hydrolysis for crossbridge recycling
calcium ATPase
hydrolyze ATP for pumping calcium into the sarcoplasmic reticulum
sodium-potassium ATPase
for maintaining the sarcolemmal concentration gradient after depolarization
amount of ATP stores
80-100g at any given time
ATP concentration may decrease up to _____.
50 - 60%
CP concentration is _____ times higher than ATP concentration.
4 - 6
Which muscle fiber type has higher concentrations of CP?
Type II
What is pyruvate?
an end result of glycolysis
Glycolysis is the breakdown of _____ —- either _____ stored in the muscle or _____ in the blood.
carbohydrate; glycogen; glucose
Pyruvate may proceed in one of two directions:
- be converted to lactate in the sarcoplasm –> fast glycolysis
- be shuttled into the mitochondria –> slow glycolysis
Lactate is the product of _____.
It is often used
- as _____, especially in Type I and cardiac muscle fibers.
- in _____ – the formation of _____ from _____ – during extended exercise and recovery
lactate dehydrogenase reaction
energy substrate; gluconeogenesis; glucose; noncarbohydrate sources
Cori cycle
lactate can be transported in the blood to the liver, where it is converted to glucose
When pyruvate enters the mitochondria, it is converted to _____ which will then enter the Krebs cycle.
acetyl-CoA
The _____ molecules enter the _____, where they can be used to resynthesize ATP.
NADH; electron transport system
oxidative phosphorylation
the resynthesis of ATP in the electron transport chain (ETC)
substrate-level phosphorylation
the direct resynthesis of ATP from ADP during a single reaction in the metabolic pathways
signs of increased ATP hydrolysis:
high concentrations of _____, _____, and _____.
slight decrease in _____ and _____.
—> increased rate of glycolysis
ADP; Pi, ammonia
pH; AMP
Markedly lower _____, _____, _____, _____, and _____ will inhibit glycolysis
pH; ATP; CP; citrate; free fatty acids
Other factors that contribute to the regulation of glycolysis:
concentrations and turnover rate of glycolytic enzymes: hexokinase, PFK (phosphofructokinase), pyruvate kinase
Lactate threshold (LT)
the exercise intensity or relative intensity at which blood lactate begins an abrupt increase above the baseline concentration
The LT usually begins at _____ of maximal oxygen uptake in untrained individuals and at _____ in aerobically trained athletes.
50 - 60%; 70 - 80%
What is onset blood lactate accumulation (OBLA)?
It occurs when the concentration of blood lactate reaches _____.
a second increase in the rate of lactate accumulation has been noted at higher relative intensities of exercise
4 mmol/L
_____ stored in fat cells can be broken down by enzyme, _____, to produce _____ and _____.
Triglycerides; hormone-sensitive lipase; free fatty acids; glycerol
Free fatty acids enters the _____, where they undergo _____, a series of reactions in which the free fatty acids are broken down, resulting in the formation of _____ and _____.
The _____ enters Krebs cycle. The _____ are carried by _____ and _____ to the electron transport chain, where ATP is produced from _____.
mitochondria; beta oxidation; acetyl-CoA; hydrogen protons
acetyl-CoA; hydrogen atoms; NADH; FADH2; ADP
Protein is broken down into _____, which are then
converted into _____
to produce ATP.
amino acids;
glucose, pyruvate, or various Krebs cycle intermediates
rate-limiting step in the Krebs cycle
conversion of isocitrate to alpha-ketoglutarate
The extent to which each of the three energy systems contributes to ATP production depends primarily on the ____ of muscular activity and secondarily on the _____.
intensity; duration
_____ is stimulated by ADP and inhibited by ATP.
Isocitrate dehydrogenase
The rate of the Krebs cycle is reduced if _____ and _____ are not sufficient to accept _____.
NAD+; FAD2+; hydrogen
ETC is stimulated by _____ and inhibited by _____.
ADP; ATP
LT represents an increasing reliance on _____.
anaerobic mechanisms
Glycolysis from one molecule of blood glucose yields a net of _____ ATP molecules.
2
Glycolysis from one molecule of muscle glycogen yields a net of _____ ATP molecules.
3
effect of event duration and intensity on primary energy system used
check notes
complete ATP resynthesis: _____
complete CP resynthesis: _____
3 - 5 minutes; < 8 minutes
Creatine phosphate (CP) can decreased markedly (_____) during the first stage of high-intensity exercise of short and moderate duration (_____) and can be almost completely depleted as a result of very intense exercise to exhaustion.
50 - 70%; 5 - 30s
The rate of glycogen depletion is related to _____.
the exercise intensity
Repletion of muscle glycogen during recovery is related to _____.
_____ of carbs per kg of bodyweight ingested every 2 hours following exercise.
post exercise carbohydrate ingestion;
0.7 - 3g
substantially decrease in blood glucose concentration: long-term exercise ( > _____) at higher intensities (> _____); because of _____
90min; 50% of maximal oxygen uptake; liver glycogen depletion
Muscle glycogen is a more important energy source than liver glycogen during _____ exercise.
moderate- and high-intensity
bioenergetic limiting factors in exercise performance:
- ATP and creatine phosphate
- muscle glycogen
- liver glycogen
- fat stores
- lower pH
EPOC
excess postexercise oxygen consumption: the oxygen uptake above resting resting values used to restore the body to the preexercise condition; also called postexercise oxygen uptake, oxygen debt, or recovery O2
6 factors responsible for EPOC
- replenishment of oxygen in blood and muscle
- ATP/CP resynthesis
- increased body temperature, circulation, and ventilation
- increased rate of triglyceride-fatty acid cycling
- increased protein turnover
- changes in energy efficiency during recovery
400 hurdles/sprint:
average time:
primary system used:
< 1min
fast glycolysis
Oxidative phosphorylation accounts for over _____ of ATP synthesis.
90%
At rest, approximately _____ of the ATP produced is derived from fats and _____ from carbohydrate.
During high-intensity aerobic exercise, almost _____ of the energy is derived from carbohydrate if an adequate supply is available.
70%; 30%
100%
