Question

passive transport occurs when molecules cross the cell membrane without using cellular energy. molecules cross the cell membrane by three main types of passive transport: simple diffusion, facilitated diffusion, and osmosis. select the true statements. simple diffusion moves molecules from areas of higher to lower concentration, while facilitated diffusion moves molecules from areas of lower to higher concentration. energy from the cell is required to move molecules from areas of higher concentration to areas of lower concentration. all molecules are able to cross the cell membrane by osmosis. as molecules move randomly, they collide with each other and spread out down their concentration gradients.

Explanation:

• Simple diffusion and facilitated diffusion both move molecules from higher to lower concentration. So the first statement is false.
• Passive transport (which includes simple diffusion, facilitated diffusion, and osmosis) does not require energy from the cell. So the second statement is false.
• Osmosis is specifically the movement of water molecules across a semi - permeable membrane. Not all molecules can cross by osmosis. So the third statement is false.
• According to the principles of diffusion, as molecules move randomly (Brownian motion), they collide and spread out down their concentration gradients. This is a key concept in passive transport.

Answer:

As molecules move randomly, they collide with each other and spread out down their concentration gradients.