The cytoskeleton of eukaryotic cells primarily consists of microtubules and microfilaments, making option 1 [(B) and (D) only] the correct answer.

Option Analysis

• (A) Peptidoglycans: Incorrect; these are bacterial cell wall components, not part of eukaryotic cytoskeletons.

• (B) Microtubules: Correct; hollow tubes of tubulin proteins that maintain cell shape, aid mitosis, and enable intracellular transport.

• (C) Chitin: Incorrect; a polysaccharide in fungal cell walls and arthropod exoskeletons, absent from cytoskeletons.

• (D) Microfilaments: Correct; actin filaments involved in cell motility, cytokinesis, and structural support.

• (E) Cellulose: Incorrect; a plant cell wall polymer, not found in eukaryotic cytoskeletons.

The cytoskeleton of eukaryotic cells forms a dynamic protein network essential for structure, motility, and division. Unlike prokaryotes, eukaryotic cytoskeletons rely on three main protein filaments: microtubules, microfilaments (actin), and intermediate filaments. This setup supports intracellular transport and adapts rapidly to cellular needs.

Core Components

• Microtubules provide rigidity and tracks for vesicle movement; they are tubulin-based and key in mitosis.

• Microfilaments drive contraction and shape changes via actin polymerization.

• Intermediate filaments offer tensile strength, though not listed in the options.

Why Other Options Fail

Peptidoglycans define bacterial walls, chitin strengthens fungi/insects, and cellulose rigidifies plants—none integrate into eukaryotic cytoplasmic scaffolds.

For GATE Life Sciences aspirants in India, mastering the cytoskeleton of eukaryotic cells distinguishes it from cell walls, aiding PYQ success like this one.