Define uniport, symport and antiport. Do they require energy ?

Explanation

### Step-by-Step Solution:

1. **Definition of Uniport**:
- Uniport refers to the transport mechanism where a single substance moves across a cell membrane in one direction. This movement occurs along the concentration gradient, meaning it goes from an area of higher concentration to an area of lower concentration.
- **Energy Requirement**: Uniport does not require energy because it is a passive transport process.

2. **Definition of Symport**:
- Symport is a transport mechanism where two different substances move across the cell membrane simultaneously in the same direction. This means that both substances are transported together, often through a carrier protein.
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