Question

multiple choice question
the plasma membrane is best described as:
a protein bilayer embedded with cholesterol and triglycerides
a cholesterol bilayer embedded with proteins and phospholipids
a phospholipid bilayer embedded with cholesterol and proteins
a layer of triglycerides with attached carbohydrates and proteins
a layer of phospholipids with attached carbohydrates and proteins

Explanation:

The plasma membrane's structure is known as the fluid - mosaic model. The basic framework is a phospholipid bilayer. Within this bilayer, cholesterol is present (to regulate fluidity) and various proteins (integral and peripheral) are embedded.

• The first option is wrong because the bilayer is of phospholipids, not proteins, and triglycerides are not a main component of the plasma membrane structure.
• The second option is wrong as the bilayer is not made of cholesterol.
• The fourth option is wrong because triglycerides are not the main structural component of the plasma membrane.
• The fifth option is wrong as the plasma membrane has a bilayer structure of phospholipids, not a single layer.
• The third option correctly describes the plasma membrane as a phospholipid bilayer with embedded cholesterol and proteins.

Answer:

C. a phospholipid bilayer embedded with cholesterol and proteins (assuming the options are labeled A - E in order, with the third option being C)