Which of the following is incorrect?

Options

A. Fructose is reducing sugar
B. Cellulose has `beta` -D Glucose units
C. DNA has D-ribose
D. Amylopectin is insoluble in water

Answer

To solve the question "Which of the following is incorrect?", we will evaluate each statement one by one.

### Step-by-Step Solution:

1. **Evaluate Statement 1: Fructose is a reducing sugar.**
- Fructose is a monosaccharide. All monosaccharides, including fructose, can act as reducing sugars because they have a free aldehyde or ketone group that can reduce other compounds.
- **Conclusion:** This statement is **correct**.

2. **Evaluate Statement 2: Cellulose has beta-D-glucose units.**
- Cellulose is a polysaccharide made up of beta-D-glucose units linked by beta-1,4-glycosidic bonds. This structure is crucial for the formation of the rigid structure of plant cell walls.
- **Conclusion:** This statement is **correct**.

3. **Evaluate Statement 3: DNA has D-ribose.**
- DNA (deoxyribonucleic acid) contains deoxyribose sugar, not ribose. The term "D" in D-ribose refers to the stereochemistry of the sugar, but in DNA, the sugar is deoxyribose, which lacks one oxygen atom compared to ribose.
- **Conclusion:** This statement is **incorrect**.

4. **Evaluate Statement 4: Amylopectin is insoluble in water.**
- Amylopectin is a component of starch and is a branched polymer made up of glucose units. Although it is less soluble than amylose, it is not completely insoluble in water; it can dissolve to some extent.
- **Conclusion:** This statement is **incorrect** as well, but it is important to note that it is more soluble than cellulose.

### Final Conclusion:
The incorrect statement among the options provided is **Statement 3: DNA has D-ribose**.