Which of the following is not strictly a biomacromolecule?

Options

A. Proteins
B. Lipids
C. Polysaccharides
D. Nucleic acid

Answer

To determine which of the following is not strictly a biomacromolecule, we need to analyze the molecular weights of the given options: proteins, lipids, polysaccharides, and nucleic acids.

### Step-by-Step Solution:

1. **Understanding Biomolecules**:
- Biomolecules are organic molecules that are essential for life processes in living organisms. They include carbohydrates, proteins, lipids, and nucleic acids.

2. **Defining Biomacromolecules**:
- Biomacromolecules are a subset of biomolecules with a molecular weight greater than 1000 Daltons. This means that any biomolecule with a molecular weight below this threshold is considered a micromolecule.

3. **Analyzing Each Option**:
- **Proteins**: The molecular weight of proteins varies widely, typically ranging from 0.54 to 2236.8 kilodaltons. Thus, proteins can be considered biomacromolecules.
- **Lipids**: The molecular weight of lipids is around 800 Daltons, which is less than 1000. Therefore, lipids do not qualify as biomacromolecules.
- **Polysaccharides**: The molecular weight of polysaccharides ranges from 22.85 to 788 kilodaltons, which is greater than 1000 Daltons in many cases, classifying them as biomacromolecules.
- **Nucleic Acids**: The molecular weight of nucleic acids (DNA and RNA) is typically greater than 5000 Daltons, making them biomacromolecules.

4. **Conclusion**:
- Based on the analysis, lipids are the only option with a molecular weight below 1000 Daltons. Therefore, the answer to the question "Which of the following is not strictly a biomacromolecule?" is **lipids**.

### Final Answer:
**Lipids** are not strictly a biomacromolecule.

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