Question

09. Which of the followine statements regarding channel proteins (shown below (shown below) is for propratic of all a. Channel proteins can assist polar molecules to cross the plasma membrane by facilitated diffusion b. The gated ion channel can allow ions to pass when stimulated to open. c. The surface of a channel protein in contact with the bilayer would likely have hydrophilic amino acids d. Water plays a role in determining which ions are allowed to pass through an ion channel. e. Aquaponins facilitate the diffusion of water across membranes. 70-71. The graph below shows the relationship between glucose concentration outside a cell and the rate of glucose diffusion across a cell membrane that has carrier proteins to facilitate diffusion Rate of diffusion Glucose concentration

Answer 1

Ans. 69. The channel proteins allow diffusion of ions along these channels down the concentration gradient. The cell membrane is a semi permeable membrane, and so it does not allow every kind of molecule to pass through it. It is made up of lipid bilayer. The portion of the channel in contact with the lipid bilayer is made up of hydrophobic amino acids while the portion of the channel forming the pore, is made up of hydrophilic amino acids as shown in the diagram.

Therefore, the statement in option c is false.