Biomembranes are similar to "protein icebergs in sea of lipids "was saying of

Options

A. Singer and Nicolson
B. Danielli and Davson
C. Gorter and Grendel
D. Helleir and Hoffmann

Answer

### Step-by-Step Text Solution

1. **Understanding the Question**: The question asks about the phrase "biomembranes are similar to protein icebergs in a sea of lipids" and who proposed this analogy.

2. **Identifying the Context**: This phrase relates to the structure of biomembranes, specifically the fluid mosaic model, which describes how proteins are embedded in a lipid bilayer.

3. **Fluid Mosaic Model**: The fluid mosaic model was proposed by scientists Singer and Nicholson in 1972. This model explains that the plasma membrane consists of a phospholipid bilayer with proteins distributed throughout.

4. **Structure of Biomembranes**: In the biomembrane:
- The lipid bilayer is composed of phospholipids, which have hydrophilic (water-attracting) heads and hydrophobic (water-repelling) tails.
- Proteins can be intrinsic (integral) or extrinsic (peripheral), and they float in or on the lipid bilayer, similar to icebergs floating in water.

5. **Significance of the Analogy**: The analogy of "protein icebergs in a sea of lipids" illustrates how proteins are embedded within the lipid bilayer, contributing to the membrane's fluidity and selective permeability.

6. **Evaluating the Options**:
- **Singer and Nicholson**: Correct, as they proposed the fluid mosaic model.
- **Daneley and Devson**: Incorrect, as they proposed an earlier model that described the membrane as a simple lipid bilayer.
- **Gorter and Grendel**: Incorrect, as they described the trilaminar nature of the lipid bilayer but did not use the iceberg analogy.
- **Heller and Hoffman**: Incorrect, as they focused on the ultra-structure of the lipid bilayer.

7. **Conclusion**: The correct answer is **Singer and Nicholson**.