Question

Some molecules are too big to pass through the phospholipid bilayer of the cell membrane. These molecules need to pass through ________________ that are embedded in the cell membrane. A) proteins B) ribosome C) cell wall D) carbohydrates

Answer 1

A) proteins. They are called bilayers that consist of lipids that surround the cell and it's organelles.

Answer 2

Answer:

(A). proteins.

Explanation:

Plasma membrane exhibits selectively permeable nature as it allows transport of certain molecules only.  

It is because of the hydrophobic nature of plasma membrane due to hydrophobic tails of lipid molecules that allows transport of small, uncharged, non-polar molecules, while large, charged or polar molecule cannot pass through the membrane.

These large, charged molecules are transported through the membrane by membrane transport proteins, which are embedded in lipid bilayer. An  example of membrane transport protein is sodium-potassium pump that transport sodium and potassium ions across the membrane.

Thus, the correct answer is (A).