Differences Between Gram Positive and Gram Negative Bacteria
S.N. | Character | Gram-Positive Bacteria | Gram-Negative Bacteria |
| 1. | Gram Reaction | Retain crystal violet dye and stain blue or purple on Gram’s staining. | Accept safranin after decolorization and stain pink or red on Gram’s staining. |
| 2. | Cell wall thickness | Thick (20-80 nm) | Thin (8-10 nm) |
| 3. | Peptidoglycan Layer | Thick (multilayered) | Thin (single-layered) |
| 4. | Rigidity and Elasticity | Rigid and less elastic | Less rigid and more elastic |
| 5. | Outer Membrane | Absent | Present |
| 6. | Variety of amino acid in cell wall | Few | Several |
| 7. | Aromatic and Sulfur-containing amino acid in cell wall | Absent | Present |
| 8. | Periplasmic Space | Absent | Present |
| 9. | Teichoic Acids | Mostly present | Absent |
| 10. | Porins | Absent | Present |
| 11. | Lipopolysaccharide (LPS) Content | Virtually None | High |
| 12. | Lipid and Lipoprotein Content | Low (acid-fast bacteria have lipids linked to peptidoglycan) | High (because of presence of outer membrane |
| 13. | Ratio of RNA:DNA | 8:1 | Almost 1 |
| 14. | Mesosomes | Quite Prominent | Less Prominent |
| 15. | Flagellar Structure | 2 rings in basal body | 4 rings in basal body |
| 16. | Magnetosomes | Usually absent. | Sometimes present. |
| 17. | Morphology | Usually cocci or spore forming rods (exception : Lactobacillus and Corynebacterium) | Usually non-spore forming rods (Exception : Neisseria) |
| 18. | Endospore formation | Some produce endospores during unfavorable conditions. | Usually not found to produce endospores. |
| 19. | Toxin Produced | Exotoxins | Endotoxins or Exotoxins |
| 20. | Pathogens | Few pathogenic bacteria belong to Gram positive group. | Most pathogens are Gram negative. |
| 21. | Nutritional Requirements | Relatively Complex | Relatively Simple |
| 22. | Resistance to Physical Disruption | High | Low |
| 23. | Cell Wall Disruption by Lysozyme | High | Low (requires pretreatment to destabilize outer membrane) |
| 24. | Susceptibility to Penicillin and Sulfonamide | High | Low |
| 25. | Susceptibility to Streptomycin, Chloramphenicol and Tetracycline | Low | High |
| 26. | Inhibition by Basic Dyes | High | Low |
| 27. | Susceptibility to Anionic Detergents | High | Low |
| 28. | Resistance to Sodium Azide | High | Low |
| 29. | Resistance to Drying | High | Low |
| 30. | Rendering | They can rendered Gram -ve by increasing acidity | They can rendered Gram +ve by increasing alkalinity |
| 31. | Examples | Staphylococcus Streptococcus Bacillus Clostridium Enterococcus | Escherichia Salmonella Klebsiella Proteus Helicobacter Pseudomonas |
Differences Between Gram Positive and Gram Negative Bacteria
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Mesosomes do not exist. Please stop using this term when it is proven to be not existing for about 40 years or more already.
Thank you, But its still in use in developing countries 🙂
interesting! .Thanks!.