Q.37 Match the bacterial structure to function
(i) Cell wall (a) Virulence factor
(ii) Glycocalyx (b) Selective permeability
(c) Attachment to surfaces
(d) Protection from osmotic lysis
(A) (i)–(b), (ii)–(d)
(B) (i)–(d), (ii)–(a)
(C) (i)–(c), (ii)–(b)
(D) (i)–(d), (ii)–(c)
The correct answer is (D) (i)-(d), (ii)-(c). Bacterial cell wall protects against osmotic lysis by providing rigid structural support, while glycocalyx enables attachment to surfaces through its sticky polysaccharide matrix. This matching tests core microbiology concepts for CSIR NET Life Sciences preparation.
Option Analysis
(A) (i)-(b), (ii)-(d): Incorrect. Cell wall does not primarily handle selective permeability—that role belongs to the plasma membrane and porins in Gram-negative bacteria. Glycocalyx mismatches osmotic protection.
(B) (i)-(d), (ii)-(a): Partially correct on cell wall but wrong on glycocalyx. While capsules (a form of glycocalyx) act as virulence factors by resisting phagocytosis, the primary function listed is attachment, not virulence.
(C) (i)-(c), (ii)-(b): Incorrect. Cell wall provides shape and lysis protection, not surface attachment. Glycocalyx lacks selective permeability, which involves lipid bilayers.
(D) (i)-(d), (ii)-(c): Correct. Peptidoglycan in cell wall withstands turgor pressure to prevent bursting in hypotonic environments. Glycocalyx (capsule/slime layer) mediates adhesion to host tissues or surfaces for colonization.
Bacterial Structures Table
| Structure | Primary Function | Key Examples/Details |
|---|---|---|
| Cell wall | Protection from osmotic lysis (d) | Peptidoglycan mesh resists water influx |
| Glycocalyx | Attachment to surfaces (c) | Polysaccharide layer forms biofilms |
Bacterial cell wall glycocalyx functions matching questions test essential microbiology knowledge for CSIR NET Life Sciences aspirants. These structures protect bacteria and aid pathogenesis through distinct roles.
Cell Wall Role
The bacterial cell wall, composed of peptidoglycan, maintains shape and counters osmotic pressure to prevent lysis in hypotonic conditions. Experiments with lysozyme demonstrate this by forming fragile protoplasts that burst without the wall.
Glycocalyx Functions
Glycocalyx, a polysaccharide layer (capsule or slime), promotes adherence to surfaces like teeth or host tissues, facilitating biofilms and colonization. It secondarily contributes to virulence by evading phagocytosis.
Exam Relevance
CSIR NET questions like this emphasize structure-function links in Unit 2 (Cell Biology & Organization). Memorize: cell wall = rigidity/lysis protection; glycocalyx = adhesion/biofilm.
