Cell membranes consist mainly of a :

Options

A. carbohydrate bilayer and proteins
B. protein bilayer and phospholipids
C. lipid bilayer and proteins
D. none of the above

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks what the cell membrane primarily consists of.

2. **Identifying Components of Cell Membrane**: The cell membrane, also known as the plasma membrane, is a crucial structure that separates the interior of the cell from the external environment.

3. **Key Components**: The main components of the cell membrane are:
- **Lipid Bilayer**: This forms the fundamental structure of the membrane, providing a barrier to most water-soluble substances.
- **Proteins**: These are embedded within the lipid bilayer and can be classified as:
- **Intrinsic (Integral) Proteins**: These span the membrane and are involved in various functions like transport and signaling.
- **Extrinsic (Peripheral) Proteins**: These are attached to the exterior or interior surfaces of the membrane and play roles in signaling and maintaining the cell's shape.

4. **Model of Cell Membrane**: The Fluid-Mosaic Model, proposed by scientists Singer and Nicholson in 1972, describes the arrangement of these components. According to this model, the lipid bilayer serves as a fluid matrix in which proteins are dispersed.

5. **Conclusion**: Based on the understanding of the structure and components of the cell membrane, the correct answer to the question is that the cell membrane consists mainly of a lipid bilayer and proteins.

**Final Answer**: The cell membrane consists mainly of a lipid bilayer and protein.

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