It is not absorbed in absence of carrier molecule

Options

A. Cholesterol
B. Fructose
C. Fatty acid
D. Monoglycerides

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question states that a certain substance is not absorbed in the absence of a carrier molecule. This implies that the absorption of this substance is dependent on a specific transporter or carrier.

2. **Identifying the Substance**: Among the options provided, we need to identify which substance requires a carrier molecule for absorption.

3. **Analyzing Fructose**: Fructose is a simple sugar that is absorbed in the intestines. Its absorption process is known as facilitated diffusion, which requires a specific carrier molecule.

4. **Role of Carrier Molecule**: The carrier molecule responsible for the absorption of fructose is known as GLUT-5. This transporter facilitates the movement of fructose across the intestinal cell membrane into the bloodstream.

5. **Absorption Mechanism**: Unlike other substances such as cholesterol, fatty acids, and monoglycerides, which can be absorbed directly into the bloodstream without a carrier, fructose specifically requires GLUT-5 for its absorption.

6. **Conclusion**: Therefore, the correct answer to the question is fructose, as it cannot be absorbed in the absence of its carrier molecule (GLUT-5).

**Final Answer**: Fructose is not absorbed in the absence of a carrier molecule.

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