Biochemical reagents are widely used for detection of biomolecules. A reagent that specifically detects a carbonyl group (C=0) in a biomolecule will yield a positive test with

Options

A. protein
B. fatty aicd
C. carbohydrate
D. all of these

Explanation

To determine which biomolecule yields a positive test with a reagent that specifically detects a carbonyl group (C=O), we can analyze the presence of carbonyl groups in proteins, fatty acids, and carbohydrates.

### Step-by-Step Solution:

1. **Understanding Carbonyl Groups**:
- A carbonyl group consists of a carbon atom double-bonded to an oxygen atom (C=O).
- Carbonyl groups are commonly found in aldehydes, ketones, and carboxylic acids.

2. **Identifying Biomolecules**:
- **Proteins**: Proteins are made up of amino acids, some of which contain carbonyl groups (specifically in the form of peptide bonds). However, not all proteins have free carbonyl groups.
- **Fatty Acids**: Fatty acids contain a carboxylic acid group (-COOH), which includes a carbonyl group. Therefore, fatty acids will consistently yield a positive test for carbonyl groups.
- **Carbohydrates**: Some carbohydrates, like glucose, have carbonyl groups (as aldehydes or ketones). However, in their cyclic forms, the carbonyl group may not be readily available for detection.

3. **Analyzing the Options**:
- **Protein**: May not yield a positive test due to the limited presence of free carbonyl groups.
- **Fatty Acid**: Will yield a positive test due to the presence of a carboxylic acid group, which contains a carbonyl group.
- **Carbohydrate**: Some carbohydrates can yield a positive test, but it depends on their structure (ring vs. linear form).

4. **Conclusion**:
- The reagent that detects carbonyl groups will yield a positive test with **fatty acids** because they consistently contain a carbonyl group in the form of a carboxylic acid.

### Final Answer:
The reagent that specifically detects a carbonyl group (C=O) in a biomolecule will yield a positive test with **fatty acids**.

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