To solve the question "Which of the following is not correctly matched with its category?", we need to analyze each option given in the question.
### Step-by-Step Solution:
1. **Identify the Options**:
The options provided are:
- Insulin, Carbohydrate
- GLUT4, Protein
- Lecithin, Glycoprotein
- Cholesterol, Lipid
2. **Analyze Each Option**:
- **Insulin, Carbohydrate**:
- Insulin is a hormone that is proteinaceous in nature, not a carbohydrate. Its primary function is to regulate glucose levels in the blood, which is a carbohydrate. Therefore, this pairing is incorrect.
- **GLUT4, Protein**:
- GLUT4 is indeed a protein, specifically a glucose transporter protein that facilitates the uptake of glucose into cells. This pairing is correct.
- **Lecithin, Glycoprotein**:
- Lecithin is a type of phospholipid, not a glycoprotein. It is primarily composed of lipid (phosphatidylcholine). Thus, this pairing is also incorrect.
- **Cholesterol, Lipid**:
- Cholesterol is a type of lipid, specifically a sterol. This pairing is correct.
3. **Determine the Incorrect Match**:
- From the analysis, we see that both "Insulin, Carbohydrate" and "Lecithin, Glycoprotein" are incorrect matches. However, since the question asks for the option that is not correctly matched, we can conclude that the most glaring error is "Lecithin, Glycoprotein" because lecithin is fundamentally a lipid, not a glycoprotein.
4. **Final Answer**:
- The option that is not correctly matched with its category is **Lecithin, Glycoprotein**.
