AP BIOLOGY

Detailed explanation-1: -Facilitated diffusion therefore allows polar and charged molecules, such as carbohydrates, amino acids, nucleosides, and ions, to cross the plasma membrane.

Detailed explanation-2: -For glucose Since glucose is a large molecule, its diffusion across a membrane is difficult. Hence, it diffuses across membranes through facilitated diffusion, down the concentration gradient.

Detailed explanation-3: -Facilitated diffusion is the passive movement of molecules along the concentration gradient. It is a selective process, i.e., the membrane allows only selective molecules and ions to pass through it. It, however, prevents other molecules from passing through the membrane.

Detailed explanation-4: -Glucose is transported across the cell membranes and tissue barriers by a sodium-independent glucose transporter (facilitated transport, GLUT proteins, and SLC2 genes), sodium-dependent glucose symporters (secondary active transport, SGLT proteins, and SLC5 genes), and glucose uniporter-SWEET protein ( SLC50 genes).

Detailed explanation-5: -Glucose transport across cell membranes can occur by carrier-mediated active transport or by a concentration gradient-dependent facilitated transport that requires a specific carrier.