LABORATORY REVIEW
DIFFUSION AND OSMOSIS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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movement of particles from [high] to [low]
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a protein “helper”
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movement of particles from [low] to [high]
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energy
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Detailed explanation-1: -Hint: Simple diffusion is the movement of particles takes place along the direction of the concentration gradient. Whereas, in facilitated diffusion, the movement of molecules can occur both ways – along the direction as well as opposite of the concentration gradient.
Detailed explanation-2: -In simple diffusion, the substance passes between the phospholipids; in facilitated diffusion there are a specialized membrane channels. Charged or polar molecules that cannot fit between the phospholipids generally enter and leave cells through facilitated diffusion.
Detailed explanation-3: -Facilitated Diffusion vs. Permeases are an example of membrane proteins used in facilitated diffusion whereas membrane protein pumps (e.g. sodium-potassium pumps) are those used in active transport. Nevertheless, they differ in the direction of transport.
Detailed explanation-4: -Two classes of proteins that mediate facilitated diffusion are generally distinguished: carrier proteins and channel proteins. Carrier proteins bind specific molecules to be transported on one side of the membrane.