THE CELL
TRANSPORT INTO AND OUT OF THE CELL
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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always remains greater inside a membrane.
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eventually becomes balanced on both sides of a membrane.
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always remains greater on the outside of a membrane.
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becomes imbalanced on both sides of a membrane.
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Detailed explanation-1: -Since diffusion moves materials from an area of higher concentration to the lower, it is described as moving solutes “down the concentration gradient". The end result is an equal concentration, or equilibrium, of molecules on both sides of the membrane. At equilibrium, movement of molecules does not stop.
Detailed explanation-2: -During diffusion, when the concentration of molecules on both sides of a membrane is the same, the molecules will continue to move across the membrane in both directions.
Detailed explanation-3: -An isotonic solution is a solution in which the amount of dissolved material is equal both inside and outside of the cell. Water still flows in both directions, but an equal amount enters and leaves the cell.
Detailed explanation-4: -At equilibrium, there is equal movement of materials in both directions. If a molecule can pass freely through a cell membrane, it will cross the membrane by diffusion (Figure below). The inside of the plasma membrane is hydrophobic, so certain molecules cannot easily pass through the membrane.