In Singer-Nicholson fluid mosaic model of cell membrane extrinsic proteins are :

Options

A. tightly attached to intrinsic proteins but can be separated easily
B. tightly attached to intrinsic proteins and cannot be separated easily
C. superficially arranged and can be separated easily
D. superficially arranged and cannot be separated easily

Explanation

### Step-by-Step Solution:

1. **Understanding the Fluid Mosaic Model**: The Singer-Nicholson fluid mosaic model describes the structure of the cell membrane, which consists of a lipid bilayer with proteins embedded within it.

2. **Identifying Protein Types**: In this model, proteins are categorized into two types: intrinsic (or integral) proteins and extrinsic (or peripheral) proteins.

3. **Characteristics of Intrinsic Proteins**: Intrinsic proteins are fully embedded within the lipid bilayer and are tightly bound to it. They play crucial roles in various cellular functions.

4. **Characteristics of Extrinsic Proteins**: Extrinsic proteins, on the other hand, are located on the surface of the membrane. They are not embedded in the lipid bilayer but are associated with it.

5. **Separation of Extrinsic Proteins**: Since extrinsic proteins are loosely attached to the membrane, they can be easily separated from the lipid bilayer without disrupting the membrane structure.

6. **Choosing the Correct Option**: Based on the characteristics of extrinsic proteins, the correct answer to the question is that they are "superficially arranged and can be separated easily."

### Final Answer:
**Extrinsic proteins in the Singer-Nicholson fluid mosaic model of the cell membrane are superficially arranged and can be separated easily.** (Option 3)

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