I know the correct answer is 3000. I do not understand why. Can someone please w
ID: 3510890 • Letter: I
Question
I know the correct answer is 3000. I do not understand why. Can someone please work this out showing all the steps and how units will cancel out. Thank you!!!!
The permeability of a lipid bilayer for glucose is 10-8 cm/sec. Consider a cell whose glucose transporter is knocked out. If it is placed in a solution that contains 1 mM glucose, how many glucose molecules will enter the cell in 10 seconds? Assume that the cell contains no glucose and the surface area of its plasma membrane is 5 m2.
a. 3000
b. 60
c. 600
d. 300
e. 6
Explanation / Answer
It is given in the question that glucose transporter is knocked out, so there will be calculation according to simple diffusion equations. Simple diffusion can be described by a modifications of Fick's Law for small non polar molecules. Since the net movement of diffusing molecules depends on concentration gradient, the rate of diffusion is directly proportional to concentration gradient across the membrane.
By Fick's law equation, rate of diffusion
dx/dt= P×A×{dc/dx}
Where P is permeability constant, A is membrane area, dc/dx is concentration gradient.
In the given question, A= 10-8 cm/sec, A= 5 microM2, dx/dc= 1 mmM
By putting aall the values in the proper unit, rate of diffusion per sec can be calculated and thus total glucose molecules in 10 sec can be calculated.