Final answer:
The correct statement regarding the movement of molecules across cell membranes is 'Three examples of passive transport are diffusion, facilitated diffusion, and osmosis.' This process does not require energy and is vital for maintaining cellular homeostasis.
Step-by-step explanation:
Among the statements regarding the movement of molecules across cell membranes provided, the one that is true is:
- c) Three examples of passive transport are diffusion, facilitated diffusion, and osmosis.
Passive transport is a biological mechanism that allows molecules to move across cell membranes without using energy. Molecules simply move from an area of higher concentration to one of lower concentration. This movement is crucial for maintaining homeostasis within the cell and ensuring that necessary substances are transported as needed.
Simple diffusion is a form of passive transport that applies to molecules that are small and nonpolar. These can cross the cell membrane without any help due to the concentration gradient.
In facilitated diffusion, proteins in the cell membrane help move substances from an area of higher concentration to an area of lower concentration, which is true for molecules that cannot freely cross the cell membrane due to their size, charge, or polarity.
Osmosis specifically refers to the movement of water through a semipermeable membrane. Water moves toward an area with a higher solute concentration, effectively moving from a region of higher water concentration to one of lower water concentration. This helps the cell maintain proper pressure and volume.