What is not true for carbohydrates?

Options

A. General formula is `C_nH_(2n) O_n`
B. Glucose is the most common monomer of carbohydrates
C. Fructose is the sweetest of all sugars
D. Do not conjugate with lipids

Answer

To determine which statement is not true for carbohydrates, we will analyze the four statements provided.

### Step-by-Step Solution:

1. **Understanding the General Formula of Carbohydrates:**
- Carbohydrates typically follow the general formula \( C_n(H_2O)_n \) or can be represented as \( C_nH_{2n}O_n \).
- This formula applies to monosaccharides, disaccharides, and polysaccharides.

2. **Checking the Formula for Monosaccharides:**
- Take glucose as an example of a monosaccharide. The molecular formula for glucose is \( C_6H_{12}O_6 \).
- If we set \( n = 6 \), then substituting into the general formula \( C_nH_{2n}O_n \) gives:
- \( C_6H_{12}O_6 \) which matches the formula for glucose. Thus, this part is true.

3. **Checking the Formula for Disaccharides:**
- Now, consider sucrose, a disaccharide, which has the formula \( C_{12}H_{22}O_{11} \).
- Setting \( n = 12 \) in the general formula \( C_nH_{2n}O_n \) gives:
- \( C_{12}H_{24}O_{12} \), which does not match the formula for sucrose. This indicates that the general formula does not hold for all carbohydrates, particularly disaccharides.

4. **Analyzing Other Statements:**
- **Statement about glucose:** "Glucose is the most common monomer of carbohydrates." This is true as glucose is a fundamental building block of many polysaccharides.
- **Statement about fructose:** "Fructose is the sweetest of all sugars." This is also true, as fructose is indeed sweeter than sucrose.
- **Statement about conjugation with lipids:** "Carbohydrates do not conjugate with lipids." This is false because carbohydrates can form glycoproteins and glycolipids when they bond with lipids.

5. **Conclusion:**
- The statement that is not true for carbohydrates is that "Carbohydrates do not conjugate with lipids." This is incorrect as carbohydrates can indeed conjugate with lipids to form glycolipids.

### Final Answer:
The statement that is not true for carbohydrates is: **"Carbohydrates do not conjugate with lipids."**