According to fluid mosaic model, plasma membrane is composed of

Options

A. Phospholipids and oligosaccharides
B. Phospholipids and hemicellulose
C. Phospholipids and integral proteins
D. Phospholipids extrinsic proteins and intrinsic proteins

Answer

### 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 Singer and Nicholson in 1972. According to this model, the plasma membrane is not a rigid structure but rather a fluid combination of various components.

2. **Components of the Plasma Membrane**: The plasma membrane is primarily composed of a phospholipid bilayer. This bilayer forms the basic structure of the membrane, providing a barrier that separates the interior of the cell from the external environment.

3. **Proteins in the Plasma Membrane**: Within this phospholipid bilayer, there are proteins that are categorized into two types:
- **Intrinsic Proteins (Integral Proteins)**: These proteins are embedded within the membrane and can span across the bilayer. They play crucial roles in transport and communication.
- **Extrinsic Proteins (Peripheral Proteins)**: These proteins are located on the surface of the membrane and are not embedded. They are often attached to the integral proteins or the phospholipid bilayer.

4. **Analyzing the Options**:
- **Option A**: Phospholipids and oligosaccharides - Incorrect, as oligosaccharides are not a major component of the plasma membrane structure.
- **Option B**: Phospholipids and hemicellulose - Incorrect, as hemicellulose is not a component of the plasma membrane.
- **Option C**: Phospholipids and integral proteins - Partially correct but incomplete, as it does not mention extrinsic proteins.
- **Option D**: Phospholipids, extrinsic proteins, and intrinsic proteins - Correct, as it encompasses all the main components of the plasma membrane according to the fluid mosaic model.

5. **Conclusion**: The correct answer is Option D: Phospholipids, extrinsic proteins, and intrinsic proteins.