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Homework Help: Maximum ratio of calcium, atp hydrolysis

  1. Feb 3, 2016 #1
    • Thread moved from the technical forums, so no HH Template is shown.
    1-The standard free energy associated to the hydrolysis of one ATP mole is -31 kJ. What would be the energy when [ATP]=5mM , [ADP]=0.5mM and [Pi]=1mM
    2-Calculate the free energy required to move 1 mol of Ca2+ ions from the outside of the cell (where [Ca2+] = 10-3) to the inside (where [Ca2+] = 10-7) when the membrane potential is -70mV and the temperature is 25°C
    3- What would be the maximum ratio of [Ca2+]out/[Ca2+]in that the atp hydrolysis would fight using the ATP ADP and PI concentrations and potential given above.

    1/ I just used the formula
    dG=dGo + RT ln ( [ADP][PI]/[ATP] )
    I found dG=-53.8 kJ

    2/ dG=RTln([Ca2+]o/[Ca2+]in) - 2*F*V
    dG=36.3 kJ

    3/ I calculated the equilibrium constants for each reaction, multiplied them to get [Ca2+]out[ADP][Pi] / [Ca2+]in[ATP] and then found the ratio from that is that correct ?
    Last edited: Feb 3, 2016
  2. jcsd
  3. Feb 8, 2016 #2
    Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
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