BIOCHEMISTRY HELP!!! 12.) The gastric H+ pump found in the plasma membrane of ga

Question

BIOCHEMISTRY HELP!!!

12.) The gastric H+ pump found in the plasma membrane of gastric mucosa cells maintains a cytostolic

concentration of K+ of 145 mM and an H+ concentration of 3.16 X 10-8 M. In the stomach, the concentration of K+ is 10 mM and the H+ ion concentration is 0.15 M.

(A) ( 2 pts) What is the pH of the cytosol of gastric mucosa cells and what is the pH of the stomach?

(B) ( 2 pts) What is the change in free energy of transporting 1 mole of H+ from the cytosol into Stomach at 37 degrees celcius? F= 96,500 J/mol(V), R = 8.3145 J/mol(K). The transmembrane electrical potential is + 70 mV (Cytosol --> Stomach ).

(C) ( 2 pts) What is the change in free energy of transporting 1 mole of K+ from the stomach into Cytosol at 37 degrees celcius? F= 96,500 J/mol(V), R = 8.3145 J/mol(K). The transmembrane electrical potential is -70 mV (Stomach--> Cytosol ).

(D) ( 2 pts) What is the change in free energy of transporting 1 mole of H+ from the cytosol into Stomach and 1 mole of K+ from the stomach into Cytosol at 37 degrees celcius? F= 96,500 J/mol(V), R = 8.3145 J/mol(K). The transmembrane electrical potential is -70 mV (Stomach --> Cytosol ).

(E) ( 2 pts) Is this transport exergonic or endergonic?__________________________________

(F) ( 2 pts) Under cellular conditions in the gastric mucosa cell, the free energy change for the hydrolysis of ATP is around -70 kJ/mol. What is the change in free energy of transporting 1 mole of H+ from the cytosol into Stomach and 1 mole of K+ from the stomach into Cytosol at 37 degreees C? F= 96,500 J/(mol)(V), R = 8.3145 J/(mol)(K). The transmembrane electrical potential is -70 mV (Stomach -->Cytosol ),when the transport is coupled with ATP hydrolysis?

(G) ( 2 pts) What type of transport is this?___________________________________________

I know that (A) is pH=8 in stomach and pH=7.5 in gastric mucosa but all the other ones are confusing me. If someone could answer them/ explain the reasoning that would be great thanks!!

Explanation / Answer

Ans A... pH = -log10 [H+] =pH of gastric mucosa cells= -log10[3.16*10-8] = around 7.5 (slightly basic)

pH of stomach = -log10[.15] = 0.82 ~ i.e around 1 (highly acidic)

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