Question

Why lipids are not considered to be a polymer or macromolecule?
• Lipids do not exist as a chain of linked monomer and they are not very big like protein, nucleic acid
• Lipids are very polar and remain in folded form
• Lipids found on surface and not fully exposed
• Lipids formed with simple molecules and they stay in globular form

• A. 1
• B. 2
• C. 3
• D. 4

Hint:

Proteins, nucleic acids and polysaccharides are true polymers because they contain repeating monomers. Lipids are not true polymers.

Answer 1

The Correct Option is A

Concept: Macromolecules are very large molecules formed by repeated joining of small repeating units called monomers. Examples:
• Proteins $\rightarrow$ amino acids
• Nucleic acids $\rightarrow$ nucleotides
• Polysaccharides $\rightarrow$ monosaccharides Lipids differ from true polymers because they are generally:
• Not formed by repeating monomer units
• Comparatively smaller in size

Step 1: Understand meaning of polymer. A polymer is: \[ \boxed{ \text{A large molecule made from repeating monomer units} } \] For example: \[ \text{Protein} = (\text{amino acids})_n \] \[ \text{DNA} = (\text{nucleotides})_n \] These molecules contain long chains.

Step 2: Understand structure of lipids. Lipids such as:
• Fats
• Oils
• Waxes
• Phospholipids are usually formed from:
• Fatty acids
• Glycerol However:
• They are not made of long repeating monomer chains. Therefore lipids are not true polymers.

Step 3: Analyze Option 1 carefully. Option 1 correctly states:
• Lipids are not formed as chains of repeating monomers.
• They are not giant macromolecules like proteins and nucleic acids. Thus this option correctly explains why lipids are not considered polymers.

Step 4: Why other options are incorrect.
• Lipids are generally non-polar, so Option 2 is incorrect.
• Option 3 does not explain polymer nature.
• Option 4 is scientifically inaccurate and incomplete.

Step 5: Choose the correct answer. Thus correct answer is: \[ \boxed{ \text{Lipids are not chains of repeating monomers} } \] Hence correct option is: \[ \boxed{(1)} \] Final Conclusion: Lipids are not considered polymers because:
• They are not formed from repeating monomer units.
• They are comparatively smaller than true biological macromolecules. Hence correct answer is: \[ \boxed{(1)} \]