Flashcards in Energy Metabolism in Muscle Deck (46)
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1
main fuel in exercising muscles?
glycogen, glucose, free fatty acids
2
energy at rest?
predominantly fatty acids
3
high intensity isometric exercise energy?
anaerobic glycolysis and creatine kinase
4
submaximal exercise, low intensity?
blood glucose and free fatty acid
5
submaximal, high intensity?
more from glycogen and glucose
-glycogen main source
6
fatigue?
when glucose and glycogen stores are depleted
7
first hour of mild, low intensity?
glucose, glucagon and free fatty acids
8
one to four hours mild to moderate prolonged exercise?
free fatty acids increase substantially
**after four hours, free fatty acids main source
9
what maintains ATP levels?
glycogen and glucose metabolism
oxidative phosphorylation
creating kinase
purine nucleotide synthesis
lipid metabolism
10
anaerobic glycolysis
high intensity, isometric activity
results in fatigue - increasead lactate - acidification
11
aerobic glycolysis
dynamic isotonic exercise
pyruvate > acetyl CoA > TCA Cycle
12
rate limiting step in glycolysis?
fructose 6 P to fructose 1,6 BP
-enzyme: PFK
13
oxidative phosphorylation
18x more ATP than glycolysis alone
14
phosphocreatine pathway
enzyme: creatine kinase
phosphocreatine + ADP > ATP + creatine
duration of reaction is very small
-first 2-7 seconds
15
where is creatinephosphate synthesized?
liver and transported to muscle cells via bloodstream
16
location of creatine kinase?
skeletal muscle, heart, brain
17
CK 1
CK BB in brain, smooth muscles of lungs
18
CK 2
CK MB in heart
19
CK 3
CK MM in skeletal muscle
20
CK in blood tests?
elevation can indicate:
MI
rhabdomyolysis
muscular dystrophy
acute renal failure
drugs
21
purine nucleotide cycle
intensely exercising muscle can generate ATP over a short period using adenylate reaction
two ADP into ATP and AMP
22
fate of AMP
deaminated to IMP
enzyme: myoadenylate deaminase
-produced ammonia
higher in type 2 fast muscle fibers**
23
AMP deaminase?
AMP > IMP
releases ammonia
24
exercise induced myopathy and most common cause of metabolic myopathy?
deficiency in AMP deaminase
25
beta oxidation
of fatty acids
at rest - main energy substrate for muscles
26
what fatty acids can cross membrane?
less than 10 carbons
-can cross inner and outer mito membranes
-undergo beta oxidation
27
what happens with long chain fatty acids?
cannot cross mito membrane
activated by long chain acyl CoA synthetase
-to CoA thioester which crosses outer membrane
28
palmitoylcarnitine
transferred across inner mito membrane
-carnitine:acylcarnitine translocase
converted back to free acyl-CoA and carntine
-enzyme: CPT II
29
CPT I
combines acyl-CoA with carnitine
acylcarnitine can then be transferred across inner membrane
30
