Carrier ions like Na+facilitate the absorption of substances like

Options

A. Fructose and some amino acids
B. Amino acids and glucose
C. Glucose and fatty acids
D. Fatty acids and glycerol

Answer

**Step-by-Step Solution:**

1. **Understanding Carrier Ions:**
- Carrier ions, such as sodium (Na+), play a crucial role in the absorption of various nutrients in the intestines.

2. **Identifying Substances Absorbed with Sodium:**
- Sodium is known to facilitate the absorption of certain substances, particularly some amino acids and glucose.

3. **Absorption Mechanisms:**
- **Amino Acids:** Most amino acids are absorbed through active transport. Some amino acids utilize sodium-dependent secondary active transport, which means they rely on the sodium gradient created by Na+/K+ ATPase pumps.
- **Glucose:** Glucose, along with galactose, is absorbed through sodium-dependent secondary active transport as well. This process involves the co-transport of sodium ions and glucose molecules across the intestinal cell membrane.

4. **Evaluating Other Options:**
- **Fructose:** Fructose is absorbed via facilitated diffusion and does not require sodium for its absorption, making this option incorrect.
- **Fatty Acids and Glycerol:** These are absorbed through simple diffusion or in the form of chylomicrons and do not rely on sodium for their absorption, making this option incorrect as well.

5. **Conclusion:**
- The correct substances that sodium ions facilitate the absorption of are some amino acids and glucose.

**Final Answer:** Carrier ions like sodium facilitate the absorption of substances like some amino acids and glucose.

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