Major classes of biologically significant large molecules include which of the following?

Options

A. Proteins
B. Nucleic acids
C. Carbohydrates and Lipid
D. All

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the major classes of biologically significant large molecules. These molecules are essential for life and are typically large in size.

2. **Identifying Biologically Significant Large Molecules**: The major classes of biologically significant large molecules are known as biomacromolecules. These include:
- **Proteins**: Large molecules made up of amino acids that perform various functions in the body, including catalyzing metabolic reactions and providing structural support.
- **Nucleic Acids**: Molecules such as DNA and RNA that store and transmit genetic information.
- **Carbohydrates**: Large molecules that serve as energy sources and structural components in cells.
- **Lipids**: A diverse group of hydrophobic molecules that include fats, oils, and steroids, playing roles in energy storage and membrane structure.

3. **Weight Consideration**: These biomacromolecules typically have a molecular weight greater than 1 kilodalton, which classifies them as large molecules.

4. **Conclusion**: Based on the classification of these biomacromolecules, the answer to the question is that all of the mentioned classes (proteins, nucleic acids, carbohydrates, and lipids) are biologically significant large molecules.

5. **Final Answer**: Therefore, the correct option that includes all these classes is option number 4, which encompasses proteins, nucleic acids, carbohydrates, and lipids.