Fluid mosaic model of plasma membrane differs from trilamellar model in

Options

A. Having proteins
B. The arrangement of phospholipids
C. The arrangement of proteins
D. The absence of proteins

Answer

### Step-by-Step Solution:

1. **Understanding the Models**:
- The **Fluid Mosaic Model** was proposed by Singer and Nicholson in 1972. It describes the plasma membrane as a flexible structure with a phospholipid bilayer that has various proteins embedded within it.
- The **Trilamellar Model** was proposed by Robertson. It describes the plasma membrane as having a trilaminar structure, consisting of a central lipid bilayer sandwiched between two layers of proteins.

2. **Key Components of Each Model**:
- In the **Trilamellar Model**:
- The plasma membrane is depicted as having a bilayer of lipids that is transparent to electrons, with dense protein layers on either side.
- The proteins are arranged in a way that they form a continuous layer on the outer surfaces of the lipid bilayer.
- In the **Fluid Mosaic Model**:
- The plasma membrane consists of a phospholipid bilayer with proteins that can move laterally within the layer, giving it a "fluid" characteristic.
- There are two types of proteins: integral proteins that span the membrane and peripheral proteins that are attached to the surface.

3. **Identifying the Differences**:
- The main difference between the two models lies in the **arrangement of proteins**:
- In the **Fluid Mosaic Model**, proteins are dispersed throughout the lipid bilayer, allowing for fluidity and flexibility.
- In the **Trilamellar Model**, proteins are arranged in a fixed manner on the surfaces of the lipid bilayer, without the same level of mobility.

4. **Conclusion**:
- Based on the differences outlined, the Fluid Mosaic Model differs from the Trilamellar Model primarily in the **arrangement of proteins** within the membrane.

### Final Answer:
The Fluid Mosaic Model of the plasma membrane differs from the Trilamellar Model in the **arrangement of proteins**.

---