Question

Channels in the plasma membrane through which molecules enter or leave the cell

• A. Membrane proteins
• B. Phospholipid tails
• C. Phospholipid polar heads
• D. All of the above

Answer 1

The correct option is A Membrane proteins

Channels in the plasma membrane through which molecules enter or leave the cell are membrane proteins. The phospholipid head and the tail make up the phospholipid bilayer. Small uncharged molecules can diffuse freely through a phospholipid bilayer. However, the bilayer is impermeable to larger polar molecules (such as glucose and amino acids) and to ions. The membrane proteins help in the transporting the larger molecules.