S.N. Characteristics Bacteria Viruses

1 Size Larger (1000 nm) Smaller (20-400 nm)

2 Cell Wall Peptidoglycan or Lipopolysaccharide No cell wall. Protein coat present instead.

3 Ribosomes Present Absent

4 Number of cells One cell (Unicellular) No cells

5 Living/Non-Living Living organisms Between living and non-living things.

6 DNA and RNA DNA and RNA floating freely in cytoplasm. DNA or RNA enclosed inside a coat of protein.

7 Infection Localized Systemic

8 Reproduce Able to reproduce by itself Need a living cell to reproduce

9 Reproduction Fission- a form of asexual reproduction Invades a host cell and takes over the cell causing it to make copies of the viral DNA/RNA. Destroys the host cell releasing new viruses.

10 Duration of illness A bacterial illness commonly will last longer than 10 days. Most viral illnesses last 2 to 10 days.

11 Fever A bacterial illness notoriously causes a fever. A viral infection may or may not cause a fever.

12 Cellular Machinery Possesses a cellular machinery Lack cellular machinery

13 Under Microscope Visible under Light Microscope. Visible only under Electron Microscope.

14 Benefits Some bacteria are beneficial (Normal Flora) Viruses are not beneficial. However, a particular virus may be able to destroy brain tumors. Viruses can be useful in genetic engineering.

15 Treatment Antibiotics Virus does not respond to antibiotics.

16 Examples Staphylococcus aureus, Vibrio cholerae, etc HIV, Hepatitis A virus, Rhino Virus, etc