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 a reagent that specifically detects a carbonyl group (C=O) will yield a positive test with, we can analyze the characteristics of the potential options: proteins, fatty acids, carbohydrates, or all of these.

### Step-by-Step Solution:

1. **Understanding Carbonyl Groups**:
- A carbonyl group is characterized by a carbon atom double-bonded to an oxygen atom (C=O). This functional group is found in various biomolecules.

2. **Identifying Biomolecules**:
- **Proteins**: Proteins are made up of amino acids, which contain amine (-NH2) and carboxyl (-COOH) groups. While they do contain carbonyl groups in the form of peptide bonds (C=O), they are not primarily defined by carbonyl groups.
- **Fatty Acids**: Fatty acids are long-chain carboxylic acids that have a carboxyl group (-COOH) at one end. The carboxyl group contains a carbonyl group (C=O), making fatty acids a suitable candidate for a positive test with a reagent that detects carbonyl groups.
- **Carbohydrates**: Carbohydrates can contain carbonyl groups as well, particularly in the form of aldehydes (in aldoses) or ketones (in ketoses). However, they are not as defined by carbonyl groups as fatty acids are.

3. **Conclusion**:
- Among the options provided, fatty acids are the biomolecules that specifically yield a positive test for a reagent detecting carbonyl groups due to their carboxylic acid structure, which contains the carbonyl group.

### 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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