In the fluid mosaic model of membrane structure, Select one: a. the proteins exist in a bilayer formation. b. the phospholipids are tightly bound in place. c. the carbohydrates are found exclusively on the intracellular surface of the membrane. d. the phospholipids act as a barrier to the passage of polar substances between the ICF and ECF e. the phospholipids arrange themselves into the shape of a channel, in order to allow ions to transport across the membrane.

D) The phospholipids act as a barrier to the passage of polar substances between the ICF and ECF

Explanation:

The plasma membrane is made up of four major kinds of molecules which include; proteins, carbohydrates, cholesterol and phospholipids.

Phospholipids are the main structure of plasma membranes. The structure of phospholipids help it serve as a barrier by playing a role in the regulation of the movement of polar molecules intracellular and extracellular fluid compartments and therefore, protect the cell.

The phospholipid structure can be described as having two ends of a head and a tail. The head end is hydrophilic or water-loving, and contains a phosphate group. The tail is hydrophobic and is made up of fatty acid chains.

Phospholipids are arranged in a bilayer with the hydrophilic head facing outwards into the ECF and ICF and the hydrophobic tail facing inwards.

Examples of phospholipids found in the plasma membrane are phosphatidylcholine and phosphatidylserine.

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