NEET · Biology · STD 11 - 8. Cell the unit of life

Select the wrong statement.

A Bacterial cell wall is made up of peptidoglycan.
B Pili and fimbriae are mainly involved in motility of bacterial cells.
C Cyanobacteria lack flagellated cells.
D Mycoplasma is a wall less microorganism.

Verified Solution

Answer & Solution

Correct Answer

(B) Pili and fimbriae are mainly involved in motility of bacterial cells.

Step-by-step Solution

Detailed explanation

(b) : Pili and fimbriae are bacterial appendages which are not involved in locomotion. Actually, pili are long fewer and thicker tubular outgrowths which develop in response to \(F^+\) or fertility factor in Gram negative bacteria. Being long they are helpful in attaching to recipient cell and forming conjugation tube. Fimbriae are small bristlelike fibres sprouting from cell surface in large number. There are \(300-400\) of them per cell. They are involved in attaching bacteria to solid surfaces.

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

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B. Reptiles	II. Branchial respiration
C. Adult amphibians	III. Cellular respiration
D. Amoeba	IV. Pulmonary and Cutaneous respiration