Lipid molecule in plasma membrane are arranged in

Options

A. Scattered
B. Series
C. Alternate
D. Head parallel

Answer

**Step-by-Step Solution:**

1. **Understanding Plasma Membrane Structure**: The plasma membrane, also known as the cell membrane, is primarily composed of lipid molecules, proteins, and carbohydrates. The arrangement of these components is crucial for the membrane's function.

2. **Fluid Mosaic Model**: The structure of the plasma membrane is best explained by the fluid mosaic model, which was proposed by Singer and Nicholson. This model describes the membrane as a dynamic and flexible structure.

3. **Lipid Bilayer Formation**: Lipid molecules in the plasma membrane are arranged in a bilayer. Each lipid molecule has a hydrophilic (water-attracting) "head" and two hydrophobic (water-repelling) "tails".

4. **Orientation of Lipids**: In the bilayer, the hydrophilic heads of the lipid molecules face outward towards the aqueous environment (both inside and outside the cell), while the hydrophobic tails are oriented inward, away from the water. This creates a barrier that is essential for the cell's integrity.

5. **Head Parallel Arrangement**: The specific arrangement of the lipid molecules in the bilayer is referred to as the "head parallel arrangement." This means that the polar heads of the lipids are aligned parallel to each other at the surfaces of the bilayer, while the hydrophobic tails are tucked inside.

6. **Quasi-fluid Nature**: The fluid mosaic model also indicates that the membrane is quasi-fluid, meaning that the lipid bilayer is not rigid but rather has a viscous nature, allowing for the movement of proteins and lipids within the layer.

7. **Conclusion**: Therefore, the lipid molecules in the plasma membrane are arranged in a head parallel arrangement, forming a bilayer structure that is essential for the membrane's function.

**Final Answer**: The lipid molecules in the plasma membrane are arranged in a head parallel arrangement.

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