Difference between Gram positive and Gram negative bacteria Archives - Online Biology Notes A Complete notes for Students Tue, 18 Dec 2018 17:54:03 +0000 en-US hourly 1 Difference between Gram positive and Gram negative bacteria https://www.onlinebiologynotes.com/difference-between-gram-positive-and-gram-negative-bacteria/ Tue, 31 Jul 2018 16:53:47 +0000 http://www.onlinebiologynotes.com/?p=1587 Difference between Gram positive and Gram negative bacteria SN. Point of distinction in characteristics Gram Positive bacteria Gram Negative bacteria 1. Gram staining reaction Retain [...]

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]]> Difference between Gram positive and Gram negative bacteria

SN.

Point of distinction in characteristics

Gram Positive bacteria

Gram Negative bacteria
1. Gram staining reaction Retain color of primary satin(crystal violet dye) and appears purple or blue Gain color of counter stain (safranin) and appears pink or red
2. Cell wall composition Peptidoglycan,lipid and teichoic acid Peptidoglycan and outer membrane (lipid, protein and LPS)
3. Cell wall thickness 20-30nm 8-12nm
4. Layer of cell wall Single layer (entirely peptidoglycan layer) Double layered ( peptidoglycan and outer membrane)
5. Peptidoglycan layer thick thin
6. Teichoic acid in cell wall Present Absent
7. Outer membrane Absent Present
8. Periplasmic space (space between inner cytoplasmic membrane and outer membrane) Absent Present
9. LPS (lipopolysaccharide) Absent Present in outer membrane
10. Braun’s lipoprotein or murein lipoprotein Absent Present
11. Porins protein Absent Present
12. Peptidoglycan cross linkage between amino acids Occurs by peptide interbridge (type and numbers of amino acids in interbridge varies among bacteria) Diaminopamelic acid of one glycan backbone form peptide bond with terminal D-alanine of adjacent glycan backbone
13. Mesosome More prominent Less prominent
14. Flagella structure 2 rings in basal body 4 rings in basal body
15. L ring structure of flagella Absent Present
16. RNA: DNA ration 8:1 Almost 1:1
17. Toxin produced Exotoxin Endotoxin (primarily) and exotoxin
18. Resistance to physical disruption High Low
19. Lysozyme digestion of cell wall peptidoglycan After lysozyme digestion gram positive bacteria become protoplast After lysozyme digestion gram negative bacteria become spheroplast
20. Susceptibility to penicillin and sulphonamide  High Low
21. Susceptibility to chloramphenicol, tetracycline and streptomycin Low High
22. Resistance to drying High Low
23. Isoelectric pH range 2.5-4 4.5-5.5
24. Nutritional requirement Relatively complex Relatively simple
25. Morphology Usually cocci and rod shaped spore forming bacteria (exception Corynebacterium and Lactobacillus are non-spore forming rod) Usually rod shape (non-spore forming except Neisseria)
26. Examples Staphylococcus

Streptococcus

Bacillus

Clostridium

Nocardia

Propionibacterium

Enterococcus

Corynebacterium

Listeria

Lactobacillus

Gardnerella

 

 ·        Escherichia

·        Salmonella

·        Klebsiella

·        Proteus

·        Helicobacter

·        Hemophilus

·        Vibrio

·        Shigella

·        Neisseria

·        Enterobacter

·        Pseudomonas

 

Difference between Gram positive and Gram negative bacteria

 

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