Differences between Gram positive bacteria and Gram negative bacteria
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Gram positive bacteria
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Gram negative bacteria
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1.
The bacteria remain coloured with
Gram staining even after washing with alcohol or acetone
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The bacteria do not
retain the stain when washed with alcohol or acetone. So these type of bacteria
are observed with another stain such as safranin.
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2.
Outer membrane is absent
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Present
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3.
Thicker cell wall. Thickness
varies from 20-80 nm
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Thin cell wall.
Thickness varies from 8-12 nm
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4.
Smooth wall
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Wavy wall and comes
in contact with plasma membrane only at a few loci.
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5.
The wall contains 70-80% peptidoglycan
(murein or mucopeptide)
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The wall contains 10-20%
peptidoglycan
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6.
Teichoic acids may be present
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Teichoic acids
absent
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7.
Very little lipid content (0-2%)
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High lipid content
(20-30%)
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8.
Lipopolysaccharide layer (LPS)
absent.
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Present
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9.
Basal body of the flagellum
contains 2 rings
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Basal body of the
flagellum contains 4 rings
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10.
Mesosomes are quite prominent
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Mesosomes are less
prominent
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11.
A few pathogenic bacteria belong
to Gram positive group
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Most of the
pathogenic bacteria belong to Gram negative group
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12.
E.g. Bacillus subtilis, Mycobacterium,
Noccardia
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E.g. Escherichia
coli
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