Which of the following carbohydrates is not a disaccharide?

Options

A. A) maltose
B. B) lactose
C. C) sucrose
D. D) galactose

Answer

To determine which of the following carbohydrates is not a disaccharide, we need to analyze each option provided:

1. **Maltose**:
- Maltose is a disaccharide composed of two glucose molecules linked together by a glycosidic bond. Therefore, maltose is indeed a disaccharide.

2. **Lactose**:
- Lactose is another disaccharide, made up of one glucose molecule and one galactose molecule. It is also linked by a glycosidic bond. Thus, lactose is a disaccharide.

3. **Sucrose**:
- Sucrose is a disaccharide formed from one glucose molecule and one fructose molecule. It is linked by a glycosidic bond as well. Hence, sucrose is a disaccharide.

4. **Galactose**:
- Galactose is a monosaccharide, which means it is a single sugar unit and not composed of two sugar units. Therefore, galactose is not a disaccharide.

Based on this analysis, the carbohydrate that is not a disaccharide is:

**Answer: Option D - Galactose**

---