In a cell's membrane, the phospholipid heads point outward toward the environment and toward the interior of the cell.

Question

Why is this arrangement of phospholipids important in regulating interactions with its surroundings?

Responses

The positively charged heads repel all negatively charged particles.
The positively charged heads repel all negatively charged particles.

The polar heads can interact with water and other charged particles.
The polar heads can interact with water and other charged particles.

The hydrophilic heads help keep the cell moist by attracting water.
The hydrophilic heads help keep the cell moist by attracting water.

The polar heads help the cell stick to other cells of similar type.

Answer 1

The most accurate response is:

The polar heads can interact with water and other charged particles.

This arrangement of phospholipids, with the hydrophilic (water-attracting) heads facing outward toward the aqueous environment and inward toward the cytoplasm of the cell, creates a barrier that is selectively permeable. It allows the cell to interact effectively with its surroundings while maintaining the internal environment necessary for cellular functions. The hydrophilic heads facilitate interactions with water-soluble substances, ions, and nutrients, helping the cell regulate the movement of materials in and out.