Macromolecules are

Options

A. nucleic acids, proteins and polysac- charides
B. nucleic acids and monosaccharides
C. amino acids and polysaccharides
D. amino acids, lipids and nucleotides

Answer

### Step-by-Step Text Solution:

1. **Definition of Macromolecules**:
- Macromolecules are large, complex molecules that are essential for various biological functions. They are typically made up of smaller units called monomers.

2. **Monomers and Polymers**:
- The basic building blocks of macromolecules are monomers. These monomers are linked together by covalent bonds to form larger structures known as polymers.

3. **Types of Macromolecules**:
- There are four major classes of biological macromolecules:
- **Proteins**: Composed of amino acids, proteins perform a vast array of functions within organisms, including catalyzing metabolic reactions and providing structural support.
- **Carbohydrates**: These include sugars and starches, which serve as energy sources and structural components. Polysaccharides, such as cellulose, are a type of carbohydrate.
- **Nucleic Acids**: These include DNA and RNA, which are responsible for storing and transmitting genetic information.
- **Lipids**: These are hydrophobic molecules, including fats and oils, that play key roles in energy storage and cellular structure.

4. **Examples of Macromolecules**:
- **Polysaccharides**: An example is cellulose, which is a carbohydrate and serves as a structural component in plant cell walls.
- **Proteins**: Enzymes are proteins that catalyze biochemical reactions.
- **Nucleic Acids**: DNA is a nucleic acid that carries genetic information.
- **Lipids**: Triglycerides are a type of lipid used for energy storage.

5. **Conclusion**:
- In summary, macromolecules are essential for life and include proteins, carbohydrates, nucleic acids, and lipids. They are formed from monomers that are linked together to create larger, functional structures.