AP BIOLOGY

Detailed explanation-1: -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. The carrier protein at the membrane binds to the glucose and alters its shape such that it can easily to be transported.

Detailed explanation-2: -Carrier proteins are responsible for the facilitated diffusion of sugars, amino acids, and nucleosides across the plasma membranes of most cells.

Detailed explanation-3: -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-4: -Answer and Explanation: The type of molecule that needs facilitated diffusion to move across the plasma membrane are large or hydrophilic molecules.

Detailed explanation-5: -Explanation: Glucose cannot move across a cell membrane via simple diffusion because it is simple large and is directly rejected by the hydrophobic tails. Instead it passes across via facilitated diffusion which involves molecules moving through the membrane by passing through channel proteins.