Your heart muscle gets most of the ATP it requires to power its continuous and r
ID: 145869 • Letter: Y
Question
Your heart muscle gets most of the ATP it requires to power its continuous and regular contractions through oxidative phosphorylation. When oxidising glucose to CO2, your heart muscle consumes O2 at a rate of 10 mol/min per g of tissue, in order to replace the ATP used in contraction and give a steady- state ATP concentration of 5 mol/g of tissue.
At this rate, how long (in seconds) would it take 1 g of heart muscle to consume an amount of ATP equal to its steady-state levels?
Assume that the complete oxidation of 1 molecule of glucose generates 30 molecules of ATP in cardiac muscle. In the process of oxidative phosphorylation the electron carriers NADH and FADH2 transfer a total of 12 pairs of electrons into the electron transport chain and these 12 pairs of electrons reduce six (6) O2. Thus 30 ATP’s are generated per 6 O2 consumed by heart muscle.
Explanation / Answer
From the ques, ATP steady state concentration in heart muscles = 5 mol/g of tissue.
i.e. 1 g of tissue has ATP = 5 mol.
As per the assumption required to be made,
Glucose + 6O2 -----à 6CO2 + 6H2O + 30 ATP
i.e. 30 moles of ATP are generated by consuming 6 moles of Oxygen
1 mole of ATP will be generated by consuming = 6/30 = 0.2 moles of oxygen
5 mol (5 x 10-6 moles) of ATP will be generated by consuming = 0.2 x 5 x 10-6
= 1 x 10-6 moles or 1 mol of oxygen
Given, Rate of oxygen consumption = 10 mol/min
i.e. 10 mol of oxygen is consumed in 1 minute or 60 seconds
Now, consumption of 10 mol of oxygen takes = 60 seconds
Consumption of 1 mol of oxygen takes = 60 seconds x (1 mol/10 mol) = 6 seconds
So, it would take 6 seconds by 1 g of heart muscles to generate ATP equal to its steady state.
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