Facilitated diffusion differs from simple diffusion in that it
- A. requires energy from ATP
- B. uses specific carrier or channel proteins in the membrane
- C. moves substances against their concentration gradient
- D. occurs only through the lipid portion of the membrane
Explanation
Facilitated diffusion still follows the concentration gradient and costs no energy, but polar molecules and ions pass through specific protein channels or carriers. Needing ATP or moving against the gradient would make it active transport, a common trap in the comparison.
Related questions
The fluid mosaic model describes the plasma membrane as
The statement that all cells arise from pre-existing cells was added to the cell theory by
The large central vacuole of a mature plant cell is bounded by a membrane called the
Which structure is normally absent from the cells of higher plants?
Plasmodesmata are