The functional characteristics of a Plasma membrane in fluid mosaic model are determined by

Options

A. extrinsic proteins
B. intrinsic proteins
C. both (1) & (2)
D. lipid molecules

Answer

### Step-by-Step Solution

1. **Understanding the Plasma Membrane**:
- The plasma membrane is a crucial structure that surrounds the cell, providing it with a barrier and maintaining the internal environment.
- It is primarily composed of lipids, proteins, and carbohydrates.

2. **Components of the Plasma Membrane**:
- **Lipid Bilayer**: The fundamental structure of the plasma membrane, which acts as a barrier to most water-soluble substances.
- **Proteins**: These are embedded within the lipid bilayer and can be classified into two types:
- **Intrinsic (or Integral) Proteins**: These proteins span the membrane and are involved in transporting substances across the membrane.
- **Extrinsic (or Peripheral) Proteins**: These proteins are located on the outer or inner surface of the membrane and play roles in signaling and structural support.
- **Carbohydrates**: These are often attached to proteins or lipids and function primarily as receptors.

3. **Functional Characteristics of the Plasma Membrane**:
- The functional characteristics of the plasma membrane, such as transport and signaling, are largely determined by the proteins present.
- Intrinsic proteins facilitate the movement of substances that cannot pass through the lipid bilayer, while extrinsic proteins can help in signaling and maintaining the structure of the membrane.

4. **Conclusion**:
- Since the question asks about the functional characteristics of the plasma membrane in the fluid mosaic model, the correct answer is that these characteristics are determined by both intrinsic and extrinsic proteins.

### Final Answer
The functional characteristics of a plasma membrane in the fluid mosaic model are determined by **both intrinsic and extrinsic proteins** (Option C).

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