As per the fluid mosaic model, how are phospholipid molecules arranged in a liipid bilayer?

Options

A. Scattered
B. Series
C. Alternate
D. Amphiphatic

Answer

To answer the question regarding the arrangement of phospholipid molecules in a lipid bilayer as per the fluid mosaic model, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Fluid Mosaic Model**:
- The fluid mosaic model describes the structure of the plasma membrane. It was proposed by scientists Singer and Nicolson in 1972 to explain the arrangement of molecules within the membrane.

2. **Structure of the Plasma Membrane**:
- The plasma membrane is primarily composed of a lipid bilayer, which consists of phospholipid molecules. These phospholipids are crucial for the membrane's structure and function.

3. **Arrangement of Phospholipid Molecules**:
- In the lipid bilayer, phospholipid molecules are arranged with their hydrophilic (water-attracting) heads facing outward towards the aqueous environment, while their hydrophobic (water-repelling) tails face inward, away from water. This arrangement creates a bilayer structure.

4. **Amphipathic Nature of Phospholipids**:
- Phospholipids are described as amphipathic molecules because they possess both hydrophilic and hydrophobic regions. The hydrophilic heads interact with water, while the hydrophobic tails avoid water, leading to the formation of the bilayer.

5. **Conclusion**:
- Based on the arrangement of phospholipid molecules in the lipid bilayer, the correct description is that they are arranged in an amphipathic manner, with hydrophilic heads on the outside and hydrophobic tails on the inside.

### Final Answer:
The phospholipid molecules are arranged in an **amphipathic** manner in the lipid bilayer.

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