Nitrous Oxide Gas Molecules Diffusing Across a Cell's Plasma Membrane

Question

Nitrous oxide gas molecules diffusing across a cell's plasma membrane is an example of
A) diffusion across the lipid bilayer.
B) facilitated diffusion.
C) active transport.
D) osmosis.
E) cotransport.

Accepted Answer

Nitrous oxide gas molecules are small, uncharged particles that can passively diffuse across the plasma membrane through the hydrophobic lipid bilayer, which constitutes the majority of the membrane's structure. This process is known as simple diffusion or passive transport, and does not require the input of energy or the presence of specific transport proteins (as in facilitated diffusion or active transport). Osmosis refers specifically to the diffusion of water molecules across a selectively permeable membrane, while cotransport involves the coordinated movement of two or more substances across a membrane.