The plasma membrane consists mainly of

Options

A. proteins embedded in carbohydrate bilayer
B. phospholipids embedded in a protein bilayer
C. proteins embedded in a phospholipids bilayer
D. proteins embedded in a polymer of glucose molecules

Answer

### Step-by-Step Text Solution:

1. **Understanding the Plasma Membrane**: The plasma membrane, also known as the cell membrane or plasmolemma, is the outermost living membrane of a cell. It serves as a barrier that separates the interior of the cell from the external environment.

2. **Components of the Plasma Membrane**: The plasma membrane is primarily composed of two main types of molecules: phospholipids and proteins.

3. **Structure of Phospholipids**: Phospholipids have a unique structure that includes a hydrophilic (water-attracting) phosphate head and two hydrophobic (water-repelling) fatty acid tails. This amphipathic nature allows them to form a bilayer in the plasma membrane.

4. **Formation of the Phospholipid Bilayer**: In the bilayer arrangement, the hydrophobic tails of phospholipids face inward, away from water, while the hydrophilic heads face outward towards the aqueous environments inside and outside the cell.

5. **Role of Proteins**: Proteins are embedded within this phospholipid bilayer. They can be classified as:
- **Transmembrane proteins**: These span the entire membrane.
- **Peripheral proteins**: These are attached to the surface of the membrane.
- **Integral proteins**: These are partially embedded in the membrane.

6. **Conclusion**: The plasma membrane consists mainly of proteins embedded in a phospholipid bilayer, which allows for various functions such as transport, signaling, and maintaining the cell's integrity.

### Final Answer:
The plasma membrane consists mainly of **proteins embedded in a phospholipid bilayer**.

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