Most biochemical macromolecules are polymers, which are chains of
a. Hydrophobic molecules
b. electrolytic molecules
c. repeating monomers
d. repeating carbohydrates
The Correct Answer and Explanation is:
Correct Answer: c. repeating monomers
Explanation:
Biochemical macromolecules are large, complex molecules essential to life. Most of these macromolecules are polymers, which are long chains made up of repeating monomers. A monomer is a small, simple molecule that can bind chemically to other similar molecules to form a polymer. This process of forming polymers is known as polymerization, and it typically occurs through dehydration synthesis, where water molecules are removed as monomers bond together.
There are four main classes of biochemical macromolecules:
- Carbohydrates
- Monomers: Monosaccharides (e.g., glucose)
- Polymers: Polysaccharides (e.g., starch, cellulose)
These provide energy and structural support.
- Proteins
- Monomers: Amino acids
- Polymers: Polypeptides
Proteins serve as enzymes, structural components, and signaling molecules.
- Nucleic Acids
- Monomers: Nucleotides (e.g., adenine, thymine)
- Polymers: DNA and RNA
These store and transmit genetic information.
- Lipids
While lipids are not true polymers because they are not made from repeating monomers, they are often grouped with macromolecules due to their large size and biological importance. Lipids include fats, oils, and steroids.
Each macromolecule’s function is largely determined by the type and sequence of its monomers. For example, the sequence of amino acids in a protein determines how it folds and, ultimately, how it functions in the body.
Now let’s review the incorrect options:
- a. Hydrophobic molecules: Not all macromolecules are hydrophobic; many are hydrophilic or have both properties.
- b. Electrolytic molecules: These are ions in solution, not the building blocks of macromolecules.
- d. Repeating carbohydrates: This applies only to polysaccharides, not to proteins or nucleic acids.
Conclusion: The most accurate description of macromolecular structure is that they are polymers composed of repeating monomers, making option c the correct answer.