The absorption of monosaccharide such as glucose in the small intestine occurs by :

Options

A. Simple diffusion method
B. Facilitated transport method
C. Active transport method
D. All of the above mention methods

Answer

To solve the question regarding the absorption of monosaccharides such as glucose in the small intestine, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding Monosaccharide Absorption**:
- Monosaccharides like glucose are absorbed in the small intestine after digestion of carbohydrates.

2. **Identifying Absorption Mechanisms**:
- There are three primary mechanisms through which glucose can be absorbed in the small intestine: simple diffusion, facilitated transport, and active transport.

3. **Simple Diffusion**:
- Glucose can move across the intestinal cell membrane through simple diffusion when the concentration of glucose is higher in the intestinal lumen than in the cells. This process does not require energy.

4. **Facilitated Transport**:
- Glucose can also be absorbed via facilitated transport, which involves specific carrier proteins in the cell membrane. These proteins help transport glucose into the cells without the expenditure of energy.

5. **Active Transport**:
- In addition to the above methods, glucose can be absorbed through active transport. This process requires energy in the form of ATP because it moves glucose against its concentration gradient, from a lower concentration in the intestinal lumen to a higher concentration in the intestinal cells.

6. **Conclusion**:
- All three methods (simple diffusion, facilitated transport, and active transport) are involved in the absorption of glucose in the small intestine. Therefore, the correct answer to the question is "all of the above."

### Final Answer:
The absorption of monosaccharides such as glucose in the small intestine occurs by all of the above methods: simple diffusion, facilitated transport, and active transport.

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