Introduction of Bacteria and Virus
Table of Contents
Bacteria are member of a large group of living unicellular microbes having size of cocci 0.5-1.0 µm while bacilli 1-10 µm×3-10µm which have cell walls but lacking an organized nucleus, including some that can cause disease like pneumonia, tuberculosis, food poisoning, etc. They are visible under light microscope. Some example of Gram positive bacteria (Staphylococcus, Pneumococcus, Streptococcus pyogenes, Streptococcus agalactiae, Enterococcus species) and Gram negative bacteria (E. coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus, Citrobacter, Enterobacter, Salmonella, and Shigella)
Virus is an infective agent that typically consists of a nucleic acid (either DNA or RNA) molecule in a protein coat, is too tiny to be seen by light microscopy, and is able to multiply only within the living cells of a host (obligate intracellular parasite). It is visible only under electron microscope and having size of smallest-parvovirus-20 nm while largest poxvirus-300 nm. Few viral diseases are influenza, AIDS, measles, polio, and COVID-19. Some example of viruses- DNA virus (Hepatitis B virus, human papillomavirus ) and RNA virus (HIV, SARS-CoV-2, Hepatitis C virus and Dengue virus)
Differences between Bacteria and Virus
The differences between bacteria and viruses are as follows-
|2||Intracellular parasite||No (except Rickettsia and Chlamydia)||Yes|
|4||Possess both DNA and RNA||Yes||No|
|5||ATP-generating metabolism||Yes (except Chlamydia)||No|
|7||Pass through bacteriological filters||Yes (except Chlamydia)||No|
|8||Sensitive to antibiotics||Yes||No|
|9||Sensitive to interferon||No||Yes|
|12||Microscopy||Compound microscope||Electron microscope|
|13||Size of Microbes||Cocci 0.5-1.0 µm while bacilli 1-10 µm×3-10µm||Smallest-Parvo virus-20 nm while largest –Pox virus-300 nm|
|14||Disease caused||Pneumonia, tuberculosis, food poisoning, and tetanus||Influenza, AIDS, measles, polio, and COVID-19|
Keynotes on Bacteria and Virus
- Rickettsia and Chlamydia of bacteria are intracelluar parasites.
- Virus is acellular organism due to lacking typical cell.
- Causative agent of COVID-19 is severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2).
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