AP BIOLOGY

Detailed explanation-1: -Facilitated diffusion is a type of passive transport. Even though facilitated diffusion involves transport proteins, it is still passive transport because the solute is moving down the concentration gradient. Small nonpolar molecules can easily diffuse across the cell membrane.

Detailed explanation-2: -Carrier proteins are present in the membrane for carrying substances which cannot cross the membrane by themselves. The carrier proteins are required for both facilitated diffusion and active transport.

Detailed explanation-3: -Glucose uses a carrier protein to cross the plasma membrane by facilitated diffusion. common glucose transporters which help in glucose transfer are GLUTs. GLUTs are integral membrane protein.

Detailed explanation-4: -Likewise, both channel and carrier proteins can transport substances across the cell membrane from high concentration to low concentration, or down their concentration gradients.