Question

For water to travel across the cell membrane at a fast rate, the water molecules travel through protein channels from areas of high concentration to low concentration. This is an example of_.

a. Facilitated diffusion
b. Active transport
c. Osmosis
d. Endocytosis

Answer 1

Water molecules travel through protein channels in a process known as osmosis, which is a form of passive transport specifically for water, involving movement from high to low water concentration areas facilitated by aquaporins.

Step-by-step explanation:

For water to travel across the cell membrane quickly, water molecules move through protein channels via a process known as osmosis. This movement is from areas of high water concentration (low solute concentration) to areas of low water concentration (high solute concentration). Osmosis is a type of passive transport and doesn't require energy because it occurs down a concentration gradient. On the cellular level, aquaporins facilitate this rapid transport of water molecules across the cell membrane.

Facilitated diffusion is also a form of passive transport where substances move across the cell membrane through specific transport proteins without the expenditure of energy. While facilitated diffusion applies to many solutes, osmosis specifically refers to the movement of water. Aquaporins play a critical role in this process, serving as channels that allow water molecules to move across the membrane more efficiently than via simple diffusion.