Bacteria and Viruses — Revision Notes

⚡ 30-Second Revision

Checked 18 October 2026.
Bacteria are prokaryotic cells; viruses are acellular and host-dependent.
Bacteriophages infect bacteria.
Antibiotic resistance is part of broader AMR.
The microorganism, not the patient, becomes resistant.
NCERT dates Ivanowsky’s filtration observations to 1892.

2-Minute Revision

Separate organisation, host and medicine target. A bacterial cell has machinery despite lacking a membrane-bound nucleus; a virus relies on a host to replicate. Bacteria include beneficial and photosynthetic forms. Antibiotics target susceptible bacteria, not a viral infection itself. AMR involves selection and spread of resistant microorganisms and needs prevention, appropriate use and surveillance.

5-Minute Revision

Classify a photosynthetic cyanobacterium and a bacteriophage by cellular organisation and role. Explain why the host name does not classify the infecting agent. Write a three-stage selection example using susceptible and resistant bacteria. Then assign infection prevention, diagnostic support and surveillance to the part of the resistance problem each addresses.

Vyyuha Quick Recall

CELL: Cellular bacteria; Entity without a cell for viruses; Locate the host separately; Link medicines to their microbial targets.