Which of the following monosaccharides is a ketohexose ?

Options

A. Glucose
B. Galactose
C. Fructose
D. Mannose

Answer

To determine which of the following monosaccharides is a ketohexose, we need to understand the definitions and characteristics of monosaccharides, particularly focusing on the terms "keto" and "hexose."

### Step-by-Step Solution:

1. **Understand Monosaccharides**:
- Monosaccharides are the simplest form of carbohydrates and cannot be hydrolyzed into simpler sugars. They are classified based on the number of carbon atoms and the type of functional group they contain.

2. **Define Ketohexose**:
- A ketohexose is a monosaccharide that contains six carbon atoms (hexose) and has a ketone functional group (keto). The general formula for a ketohexose is C6H12O6.

3. **Identify Common Monosaccharides**:
- Some common monosaccharides include:
- Glucose (an aldohexose)
- Galactose (an aldohexose)
- Mannose (an aldohexose)
- Fructose (a ketohexose)

4. **Analyze the Options**:
- If the options provided include glucose, galactose, mannose, and fructose, we can identify:
- Glucose, galactose, and mannose are all aldoses (they contain an aldehyde group).
- Fructose is the only one that contains a ketone group, making it a ketohexose.

5. **Conclusion**:
- Therefore, the monosaccharide that is a ketohexose among the options is **Fructose**.