Draw and label a schematic of the phospholipid bilayer. Which part of the phospholipid bilayer will be embedded in the membrane? Explain the reason.
The correct answer and explanation is :
In the phospholipid bilayer, the hydrophilic (water-attracting) heads of the phospholipids face outward, toward the aqueous environment inside and outside the cell, while the hydrophobic (water-repelling) tails point inward, away from the water. This structure creates a stable barrier between the cell’s internal and external environments, with the hydrophilic heads interacting with the water, and the hydrophobic tails forming a non-polar region in the middle of the bilayer.
When it comes to embedded proteins, certain proteins have hydrophobic regions that allow them to be inserted into the membrane. These hydrophobic regions interact with the hydrophobic tails of the phospholipids, helping anchor the protein in the membrane. These embedded proteins often serve functions like transport (e.g., channels and pumps), signaling, and structural support.
Explanation:
- The hydrophilic heads face the external and internal aqueous environments of the cell to interact with water, which is essential for maintaining cellular integrity and function.
- The hydrophobic tails, which are non-polar, are shielded from water and are positioned inside the bilayer, preventing water and water-soluble molecules from crossing the membrane freely.
- Embedded proteins are often amphipathic, meaning they have both hydrophobic and hydrophilic regions. The hydrophobic regions allow the proteins to be embedded in the middle of the bilayer, where they can carry out functions such as transporting molecules across the membrane or facilitating cell communication.
This unique arrangement of phospholipids and proteins creates a selective permeability barrier, crucial for maintaining the cell’s environment.