Carrier proteins which are present in the cell membrane facilitate the transport of

Options

A. Non - polar molecules
B. Hydrophobic molecules
C. Polar - molecules
D. Water

Answer

To solve the question regarding the role of carrier proteins in the cell membrane, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Carrier Proteins**:
- Carrier proteins are specialized proteins embedded in the cell membrane that facilitate the transport of substances across the membrane. They are essential for moving molecules that cannot freely diffuse through the lipid bilayer.

**Hint**: Remember that carrier proteins are integral to the function of the cell membrane in transporting substances.

2. **Identifying the Types of Molecules**:
- The question provides options: non-polar molecules, hydrophobic molecules, polar molecules, and water. We need to determine which of these types of molecules carrier proteins can transport.

**Hint**: Think about the properties of the cell membrane and what types of molecules typically require assistance to cross it.

3. **Analyzing the Cell Membrane**:
- The cell membrane is selectively permeable. This means it allows certain types of molecules to pass while blocking others. Non-polar and hydrophobic molecules can often pass through the lipid bilayer without assistance, while charged and polar molecules require carrier proteins.

**Hint**: Recall that the lipid bilayer of the cell membrane is hydrophobic, which affects how different types of molecules can cross it.

4. **Determining the Correct Answer**:
- Since carrier proteins facilitate the transport of charged and polar molecules, we can conclude that the correct answer from the options provided is **polar molecules**.

**Hint**: Focus on the characteristics of the molecules that need assistance to cross the membrane.

5. **Final Conclusion**:
- The carrier proteins present in the cell membrane primarily facilitate the transport of **polar molecules**.

### Final Answer:
The correct answer is **polar molecules**.