Select an incorrect statement for facilitated diffusion and active transport

Options

A. Transport rate reaches a maximum when all the protein
transporters are saturated
B. Proteins transporters are sensitive to inhibitors that react with
protein side chains.
C. Proteins transporters use energy to carry substances across the cell membrane.
D. Both follow saturation kinetics

Answer

To solve the question "Select an incorrect statement for facilitated diffusion and active transport," we will analyze the characteristics of both processes and evaluate the provided statements.

### Step-by-Step Solution:

1. **Understand Facilitated Diffusion:**
- Facilitated diffusion is a type of passive transport.
- It does not require energy (ATP) for the movement of substances.
- It occurs across a biological membrane with the help of protein transporters.
- The transport rate can reach a maximum when all protein transporters are saturated.

2. **Understand Active Transport:**
- Active transport is a process that requires energy (usually in the form of ATP).
- It also occurs across a biological membrane.
- Like facilitated diffusion, it utilizes protein transporters to move substances.
- Active transport can move substances against their concentration gradient.

3. **Evaluate the Statements:**
- **Statement A:** "Transport rate reaches a maximum when all the protein transporters are saturated."
- This statement is true for both facilitated diffusion and active transport.
- **Statement B:** "Protein transporters are sensitive to inhibitors that react with protein side chains."
- This statement is also true; inhibitors can block transporters and halt transport.
- **Statement C:** "Protein transporters use energy to carry substances across the cell membrane."
- This statement is false for facilitated diffusion, as it does not use energy. It is true for active transport.
- **Statement D:** "Both follow saturation kinetics."
- This statement is true; both processes exhibit saturation kinetics.

4. **Identify the Incorrect Statement:**
- The incorrect statement is **Statement C**, as it inaccurately implies that all protein transporters (including those involved in facilitated diffusion) use energy.

### Final Answer:
The incorrect statement is **C: "Protein transporters use energy to carry substances across the cell membrane."**

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