Final answer:
The plasma membrane has a higher concentration of sphingomyelin, cholesterol, and phosphatidylcholine compared to the ER membrane. Cholesterol is located within the tail bilayer, and unsaturated phospholipids, with double bonds in their tails, contribute to membrane fluidity. The correct answer is option A,C and D.
Step-by-step explanation:
Compared to the endoplasmic reticulum (ER) membrane, the plasma membrane contains a higher concentration of certain lipids.
The correct answers to which components are more abundant in the plasma membrane are:
- A) Sphingomyelin - One of the key sphingolipids found in the plasma membrane.
- C) Cholesterol - Cholesterol is particularly enriched in the plasma membrane, influencing its fluidity and stability.
- D) Phosphatidylcholine - A major component of eukaryotic plasma membranes, including that of animal cells.
These components are integral in providing the structure and function specific to the plasma membrane. For instance, cholesterol is embedded within the tail bilayer of the membrane, as it intercalates among the fatty acid tails of phospholipids, where it regulates the membrane fluidity.
Additionally, unsaturated phospholipids like phosphatidylcholine contribute to membrane fluidity through the presence of double bonds in the fatty acid tail.
Phospholipids, overall, are critical components of the plasma membrane, providing the essential barrier that separates the internal components of the cell from the external environment.