Multiple Choice
In passive transport, how does increasing temperature generally affect the rate of diffusion of small molecules across a membrane or through a fluid?
24
views
9. Transport Across Membranes
Passive Transport: Diffusion and Osmosis
Multiple Choice
In the context of passive transport (diffusion and osmosis), facilitated diffusion is best described as which of the following?
A
A passive process in which water moves through aquaporins from lower to higher solute concentration, carrying solutes with it
B
A passive process in which solutes move down their concentration gradient through membrane proteins without direct ATP use
C
A vesicle-mediated process that imports solutes by endocytosis regardless of concentration gradient
D
An active process that uses ATP to pump solutes against their concentration gradient through carrier proteins
Verified step by step guidance1
Understand the definition of passive transport: it involves the movement of molecules across the cell membrane without the use of cellular energy (ATP), typically moving down their concentration gradient.
Recognize that facilitated diffusion is a type of passive transport where specific membrane proteins (such as channel or carrier proteins) help solutes move across the membrane without energy expenditure.
Differentiate facilitated diffusion from osmosis: osmosis specifically refers to the movement of water molecules through aquaporins, while facilitated diffusion involves solutes.
Eliminate options that describe active transport or vesicle-mediated processes, as these require energy or do not depend on concentration gradients.
Conclude that facilitated diffusion is best described as a passive process where solutes move down their concentration gradient through membrane proteins without direct ATP use.
Related Videos
Related Practice
