Describe the role played by protein pumps during active transport in plants.

Explanation

### Step-by-Step Text Solution:

1. **Understanding Active Transport**: Active transport in plants refers to the movement of substances against their concentration gradient. This means that materials are transported from an area of lower concentration to an area of higher concentration.

2. **Role of Protein Pumps**: The process of active transport is facilitated by specific protein pumps located in the cell membrane. These pumps are known as transmembrane proteins.

3. **Formation of Protein-Substance Complex**: The protein pumps first bind to the substance that needs to be transported. This binding forms a complex between the protein pump and the substance.

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