Passive transport of molecules across the membrane implies that the movement occurs

Options

A. Irrespective of energy requirement
B. with the requirement of energy
C. Without energy requirement
D. from low concentration to high concentration

Answer

### Step-by-Step Solution:

1. **Understanding Passive Transport**:
- Passive transport refers to the movement of molecules across a cell membrane without the use of energy. This process relies on the natural kinetic energy of the molecules and occurs along the concentration gradient.

2. **Concentration Gradient**:
- Molecules move from an area of higher concentration to an area of lower concentration. This is known as moving "down" the concentration gradient.

3. **Energy Requirement**:
- In passive transport, no energy (ATP) is required. This distinguishes it from active transport, which does require energy to move molecules against their concentration gradient.

4. **Types of Passive Transport**:
- There are two main types of passive transport:
- **Simple Diffusion**: Movement of small or nonpolar molecules directly through the lipid bilayer.
- **Facilitated Diffusion**: Movement of larger or polar molecules through protein channels or carriers in the membrane.

5. **Conclusion**:
- Therefore, passive transport of molecules across the membrane implies that the movement occurs **without energy requirement** and **from high concentration to low concentration**.

### Final Answer:
Passive transport of molecules across the membrane implies that the movement occurs **without energy requirement** and **from high concentration to low concentration**.

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