Question

Which of the following describes osmosis?
A
Oxygen transfers into red blood cells through small gaps in the cell membrane from oxygen-rich environment surrounding the cells.
B
Large molecules are brought into the cell by wrapping the cell membrane around the molecules to form a vesicle.
C
Water moves across the cell membrane from the side with high osmotic pressure towards the side with low osmotic pressure.
D
Membrane proteins provide a pathway for larger particles to move across the cell membrane and bring the cell and environment closer to equilibrium.

Answer 1

None of the options are correct.

Correct definition of osmosis: the passive movement of water across a semipermeable membrane from the side with lower solute concentration (lower osmotic pressure) toward the side with higher solute concentration (higher osmotic pressure).

Why the choices are wrong:
- A describes simple diffusion of oxygen, not osmosis.
- B describes endocytosis (vesicle formation), not osmosis.
- C states the direction of water flow incorrectly (it says from high osmotic pressure → low, which is the reverse).
- D describes facilitated transport of solutes via membrane proteins, not osmosis (and refers to larger particles).