The compound valinomycin is a carrier ionophore that selectively binds IC on one

Question

The compound valinomycin is a carrier ionophore that selectively binds IC on one side of a membrane, diffuses through the membrane, and releases the IC on the other side of the membrane. One valinomycin molecule can transport 10^4 K+ per second across a membrane (from high concentration to low concentration of IC). For a cylindrical red blood cell with a diameter of 7.5 Mu.m and a height of 2 MuM, how long would it take for 100 molecules of valinomycin to change the intracellular concentration of IC from 140 mM to 130 mM? (Assume that transport of K+ is unidirectional and that all valinomycin molecules are saturated with IC and thus working at maximal rates.)

Explanation / Answer

Calculate the difference between the concentrations

140-130=10 mM

Use Avogadro’s number

1 mole = 6.02214179×1023

10 mM = 10*10-3 moles

= 10*10-3*6.02214179×1023

= 60,221,4179*1013

One valinomycin can transport 104 K+ molecules per second

Calculate the total number of K+ molecules transported by 100 molecules of valinomycin

100*104= 106

Calculate the total time required to transport 60,221,4179*1013 K+ molecules

= 60,221,4179*1013/106

= 60*1014 seconds

It takes about 60*1014 seconds to change the intracellular concentration from 140 mM to 130 mM.

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.