Question

Consider a uniport system where a carrier protein transports an uncharged substance A across a cell membrane. Suppose that at a certain ratio of [A]_inside to [A]_outside, the delta G for the transport of substance A from outside the cell to the inside, A_outside rightarrow A_inside, is 11.1 kJ/mol at 25 degree C. What is the ratio of the concentration of substance A inside the cell to the concentration outside? [A]_inside/[A]_outside = Choose the true statement about the transport of A under the conditions described above. Since delta G is positive, the ratio [A]_inside/[A]_outside must be less than one. Movement of A_inside to A_outside will be spontaneous. Increasing [A]_outside will cause delta G for movement of A_outside to A_inside to become a larger positive number. Decreasing the concentration of the uniport protein in the membrane will cause AG to become a smaller positive number.

Answer 1

$\Delta$G⁰   = 11.1Kj/mole = 11100J/mole

T      = 25+ 273 = 298K

A _outside --------> A _inside

K   = [A] _inside/[A] _outside

$\Delta$G⁰    = -RTlnK

-11100 = -8.314*298*2.303log [A] _inside/[A] _outside

log [A] _inside/[A] _outside    = 11100/-5705.8483

log [A] _inside/[A] _outside     = -1.945

[A] _inside/[A] _outside           =-10^1.945

[A] _inside/[A] _outside         = -88.1 >>>> answer

b) option b is correct

gelta G is negative reaction is spontaneous