Question

A cell membrane that transports glucose, ions, or other charged or polar molecules is likely to have a higher percentage and greater variety of proteins than one that does not transport these molecules.

Answer 1

Answer: True

Explanation:

A cell membrane consists of a lipid bilayer made of polar phosphate head and a nonpolar lipid tail. It is semipermeable and regulates the transport of materials through it. For this, it is selectively permeable and since it is made of lipids, hydrophobic and small polar molecules can diffuse easily through it by simple diffusion and down their concentration gradient. However, polar molecules, large molecules (such as glucose) and ions are not able to pass through it because they are repelled.

To accomplish the transport of these molecules that can not diffuse, proteins embebbed in the membrane function as carriers that enable the transport of polar molecules, large molecules and ions by passive (through facilitated diffusion, down its concentration gradient) or active transport (movement against its concentration gradient).