Lecture 8: Metabolism 6 (final) Flashcards
t/f our bodies are able to directly use the chemical energy from food we digest. why/why not
false
for cells, the nergy in the C H bonds from food has to be converted to ATP
how is ATP created, basically
moving phosphate molecule from ADP to ATP and back to ADP to generate energy
what happens when ATP is hydrolized
it can split the terminals phosphate from the compound, once it it’s hydrolized, energy is released; roughly 70% of total energy released is degraded to heat while the remaining energy is used to perform work
what can be used to convert ADP to ATP?
glucose
what are three ways ATP is produced
creating phosphate, glycolysis, oxidative respiration
explain the creatine phosphate mechanism. what happens has the onset of exercise?
plays a vital role in muscle contraction as it replenishes ATP for the immediate muscle contractions
the CP system supplies contracting muscle cells the with the first few seconds of ATP, enabling glycolysis to be initiated before the steps of ATP are exhausted
if there’s a lot of ATP inside the cell, wouldn’t be a constant source of energy?
although there’s lot of ATP, it takes a lot of time to access it (convert it from ADP)
how is glycolysis broken down into glucose? is this an optimal producer of ATP? why not?
via glycolytic enzymes; present in the cytosol of cell and is much more complex than the CP system
it’s not an optimal producer of ATP as it produces only small amounts of ATP as compared to oxidative phosphorylation, but does allow access to ATP in the absence of O2
we don’t get ATP molecules per molecule of glucose metabolized
what’s the trade-off of glycolysis
it produces glucose quickly, but forms a lot of metabolites that eventually exhaust the muscles
explain the oxidative respiration mechanism? what is it known as? Is it considered aerobic or anaerobic?
breaks down fuel with the aid of O2 in the mit. and is known as cellular respiration
it is considered aerobic due to the presence of O2
is OR utilized for short or long periods of exercise?
as it can produce an abundant ATP supply for extended periods, this system allows moderate activity to continue for a prolonged period of time without fatigue
at rest, the metabolic requirements of the body are dominated by what organs? what is the standard resting metabolic rate?
brian, kidneys, liver, muscles, and heart
3.5 mL/min/kg which is termed 1 MET (metabolic equivalent)
does liver decrease or increase metabolism during exercise?
decreases cuz it releases glucose (increase if its converting glucose into glycogen; needs nergy)
explain AV-O2 difference? what does this depend on?
as the working muscles extract o2 from the capillaries, there is a widening of the difference between arterial and venous o2 concentration
the difference depends on both carrying capacity of o2 by the blood and oxidative potential of mit.
what does knowing the cardiac output (oxygen delivery)
and AV-O2 difference (o2 utilization) mean?
enables the rate of o2 uptake (vo2) to be determined by the Fick equation:
VO2 = Q x (AV-O2)
how does training improve O2 delivery and use
With consistent training, the same workload (exercise intensity) becomes easier because muscles become more efficient at using oxygen (O₂).
Trained muscles can extract more O₂ from the blood, reducing the need for excessive cardiac output (Q).
AV-O₂ difference increases → meaning muscles extract more O₂ from the blood, improving efficiency.
This reduces the need for a high cardiac output (Q), so the heart doesn’t have to work as hard to deliver oxygen.
how is VO2 measured? what happens during sub maximal exercise, and as exercise intensity inc?
VO2 is measured most commonly using metabolic carts to assess changes in respiratory gas fractions and volumes
an almost linear relationship exists between cardiac output and O2 uptake
as exercise intensity increases the muscles extract more O2 and therefore more AV- O2 difference widens
