. Which of the following is an appropriate description of the arrangement of the cell membrane?
A. Fluid phospholipid bilayer containing embedded proteins
B. Rigid carbohydrate bilayer containing embedded phospholipids
C. Rigid layer of phospholipids with proteins on the outer surface
D. Layers of protein and carbohydrates forming a fluid structure
Letter A would be the answer.
To determine the correct answer, let's break down each option and understand the arrangement of the cell membrane:
A. Fluid phospholipid bilayer containing embedded proteins: This option correctly describes the arrangement of the cell membrane. The cell membrane is composed of a double layer of phospholipids, with their hydrophobic tails facing inward and their hydrophilic heads facing outward. This bilayer structure gives the membrane its fluidity. In addition to phospholipids, there are also embedded proteins within the lipid bilayer.
B. Rigid carbohydrate bilayer containing embedded phospholipids: This option is incorrect. The cell membrane does not have a rigid carbohydrate bilayer. While carbohydrates play a role in cell recognition and signaling, they are not the main component of the cell membrane.
C. Rigid layer of phospholipids with proteins on the outer surface: This option is incorrect. The cell membrane is not a rigid layer of phospholipids. As mentioned earlier, the membrane is fluid due to the presence of phospholipids and therefore can move and change shape. Additionally, proteins are embedded throughout the membrane, not just on the outer surface.
D. Layers of protein and carbohydrates forming a fluid structure: This option is incorrect. While proteins and carbohydrates are indeed present in the cell membrane, they do not form layers. Rather, they are embedded within the phospholipid bilayer.
Therefore, the appropriate description of the arrangement of the cell membrane is A. Fluid phospholipid bilayer containing embedded proteins.