immediate system Flashcards
how much ATP is stored in the body
~80-100g mostly in the muscle cells
(don’t need tons - it’s recycled)
does concentration of ATP change
no - unless you go to 250% of VO2max
- body is very sensitive to changes in ATP
what are the defense mechanisms (alarm systems) for low ATP (ATP doesn’t trigger resynthesis on its own)
ADP, AMP, and Pi increase
- activate ATP resynthesis process
Ca2+ increases
- increased Ca2+ in the cell will increase ATP because the muscle knows that ATP is needed for contraction
what is the difference in NADH and NAD+ at rest vs exercise
NADH = abundant at rest
NAD = goes up with exercise
- when NAD goes up then the body knows ATP needs to be resynthesised
what are the 3 sources of the immediate system
stored ATP
PCr
ADP
what activates creatine kinase
increase in ADP
decrease in ATP
what is the role of creatine kinase
facilitates the reaction:
PCr + ADP + H+ —> ATP + Cr
(PCr transfers a phosphate to ADP to form ATP)
why is there more PCr in the muscle than ATP
needed to maintain the homeostasis of ATP
what is the adenylate kinase reaction
ADP + ADP —> ATP + AMP
- insignificant source of ATP
AMP + H+ –> IMP + NH4+
when does the adenylate kinase reaction occur
during very high intensity exercise
rare scenario
why does the adenylate kinase reaction increase recovery time
removes adenine nucleotides from the pool
- body also doesn’t like the production of AMP because it’s unstable and the body immediately breaks it down into nitrates and IMP
what is the difference in the first few seconds vs at exhaustion for ATP and PCr in the immediate system
first few seconds
- ATP maintained
- PCr decreases
exhaustion
- both ATP and PCr decrease
- prevents further muscle contractions
how long do stored ATP and PCr last
can sustain energy for 3-15sec
beyond that time, other energy systems should be activated
what is a rate limiting enzyme
enzymes that contribute to the control of the rate of reaction
usually located in an early step of a pathway (early phases of reaction)
what does the activity of an RLE depend on
accumulation of substrate further down the pathway
