Type of transport across the biomembrane without the help of proteins is

Options

A. Facilitated diffusion
B. Active transport
C. Simple diffusion
D. Diffusion via symport

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for a type of transport across the biomembrane that does not involve proteins.

2. **Identifying Types of Transport**:
- **Facilitated Diffusion**: This process requires carrier proteins to help move substances across the membrane along the concentration gradient.
- **Active Transport**: This process uses energy (ATP) and involves proteins to move substances against the concentration gradient.

3. **Defining Simple Diffusion**:
- Simple diffusion is a passive transport mechanism that allows substances to move across the membrane directly, without the need for proteins. It occurs along the concentration gradient, meaning substances move from an area of higher concentration to an area of lower concentration.

4. **Examples of Simple Diffusion**:
- A common example is the diffusion of gases like oxygen and carbon dioxide across cell membranes. Another example is the spreading of perfume in a room, where the scent molecules move from a concentrated area to a less concentrated area.

5. **Conclusion**: Based on the definitions and examples, the type of transport across the biomembrane without the help of proteins is **Simple Diffusion**.

### Final Answer:
The type of transport across the biomembrane without the help of proteins is **Simple Diffusion**.

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