Movement of materials against concentration gradient is due to

Options

A. Osmosis
B. Active transport
C. Diffusion
D. Passive transport

Answer

**Step-by-Step Solution:**

1. **Understanding Concentration Gradient:**
- A concentration gradient refers to the difference in the concentration of a substance between two areas. Materials naturally move from areas of high concentration to areas of low concentration.

2. **Identifying the Types of Transport:**
- There are two main types of transport mechanisms: passive transport and active transport.
- Passive transport occurs along the concentration gradient (from high to low concentration) and does not require energy.
- Active transport occurs against the concentration gradient (from low to high concentration) and requires energy.

3. **Evaluating the Options:**
- **Osmosis:** This is the movement of water across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration. This process does not involve movement against the concentration gradient.
- **Active Transport:** This is the correct answer. It involves the movement of materials from an area of lower concentration to an area of higher concentration, which is against the concentration gradient. This process requires energy, usually in the form of ATP.
- **Diffusion:** This is the movement of materials from an area of higher concentration to an area of lower concentration, which is along the concentration gradient. Thus, it does not involve movement against the gradient.
- **Passive Transport:** Similar to diffusion, this involves the movement of substances from high to low concentration and does not require energy.

4. **Conclusion:**
- The movement of materials against the concentration gradient is due to **active transport**, which requires energy to move substances from areas of lower concentration to areas of higher concentration.

**Final Answer:**
The movement of materials against concentration gradient is due to **active transport**.

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