Multiple Choice
Which statement best describes diffusion in the context of passive transport across biological systems?
35
views
9. Transport Across Membranes
Passive Transport: Diffusion and Osmosis
Multiple Choice
How are osmosis and diffusion alike in passive transport?
A
Both involve the net movement of substances down their concentration gradient and do not require cellular energy input (ATP).
B
Both require membrane transport proteins (channels or carriers) to move molecules across the plasma membrane.
C
Both move solutes from lower concentration to higher concentration to maintain homeostasis.
D
Both occur only in living cells and stop immediately when the cell dies.
Verified step by step guidance1
Step 1: Understand the definitions of osmosis and diffusion. Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration, while osmosis specifically refers to the diffusion of water across a selectively permeable membrane.
Step 2: Identify the common feature of passive transport shared by both processes. Both osmosis and diffusion involve the net movement of substances down their concentration gradient, meaning from higher to lower concentration, without the use of cellular energy (ATP).
Step 3: Analyze the role of membrane proteins. Unlike facilitated diffusion, simple diffusion and osmosis do not necessarily require membrane transport proteins; osmosis occurs through the lipid bilayer or aquaporins, and diffusion can occur directly through the membrane or via proteins depending on the molecule.
Step 4: Evaluate the direction of movement. Both processes move substances from higher to lower concentration, not the other way around, so the statement about moving solutes from lower to higher concentration is incorrect.
Step 5: Consider the conditions under which these processes occur. Both osmosis and diffusion can occur in living and non-living systems as long as there is a concentration gradient and a permeable barrier; they do not stop immediately when a cell dies.
Related Videos
Related Practice
