The cookies is used to store the user consent for the cookies in the category "Necessary". This cookie is set by GDPR Cookie Consent plugin. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". The cookie is used to store the user consent for the cookies in the category "Analytics". These cookies ensure basic functionalities and security features of the website, anonymously. Necessary cookies are absolutely essential for the website to function properly. You may also Prokaryotes, Eukaryotes and Archaea: A comparison Difference Between Prokaryotes and Difference Between Prokaryotic and Difference Between Prokaryotic and Eukaryotic Translation Lecture Notes Biology PPTs Video Tutorials Biology MCQ Question Bank Difference between Practical Aids Mock Tests (Online) Biology Exams More Lecture Notes from Easy Biology Class…īotany Zoology Biochemistry Genetics Cell & Molecular Biology Biotechnology Physiology & Endocrinology Plant Physiology Microbiology Immunology Embryology Ecology Evolution Biophysics Research Methodology Biostatistics Chemistry for Biologists Physics for Biologists Most of them are pathogenic to human and other animals Very few are pathogenic to human and other animals Shows low resistance to sodium azide solutionĬells shows high susceptibility towards penicillins and sulfonamide antibioticsĬells shows low susceptibility towards penicillins and sulfonamide antibioticsĬells show low susceptibility towards streptomycin, chloramphenicol and tetracyclinesĬells shows high susceptibility towards streptomycin, chloramphenicol and tetracyclinesĬell wall is highly susceptible to degradation by lysozyme enzymeĬell wall is less susceptible to degradation by lysozyme enzyme Shows high resistance to sodium azide solution Gram negative bacteria are more resistant to antibioticsĬannot be killed by vancomycin antibiotic Gram positive bacteria are more susceptible to antibiotics Produce endospores spores during unfavourable conditionsįlagella with four rings in the basal body Porins (proteinaceous membrane channels) are absent Periplasmic space absent or if present, very narrow S-layer is attached to the outer membrane S-layer is attached to the peptidoglycan layer Muramic content of cellwall is less, 2 – 5% of dry weightĬell wall is resistant to alkalis and insoluble in 1% KOH solutionĬell wall is sensitive to alkalis and soluble in 1% KOH solutionĬell is highly resistant to physical disruptionsĬell is highly susceptible to physical disruptions Muramic acid content of cell wall is more, 16 – 20% of dry weight Thickness of cell wall varies from 7.5 to 12 nm Thickness of cell wall varies from 15- 20 nm, sometimes up to 80 nm The elasticity of cell wall is due to the less amount of peptidoglycan (2 – 12 %) The rigidity of cell wall is due to the high proportion of peptidoglycans (80%) Retain the colour of crystal violet after washing with alcohol (de-staining solution)Ĭolour of crystal violet will not be retained after washing with de-staining solutionĮxamples: Bacillus subtilis, Streptococcus, Lactobacillus, Leuconostoc, ClostridiumĮxamples: Escherichia coli, Rhizobium, Vibrio, AcetobacterĬell wall single layered, straight and even Similarities between Gram Positive and Gram Negative BacteriaĪppears as dark violet or purple coloured under microscope after Gram stainingĪppears as pink or red coloured after Gram staining Even though all bacterial species cannot be differentiated based on gram staining technique, this method has immense application in clinical diagnostics and biological researches. Gram staining method is useful in differentiating majority of bacterial species into two broad categories. Gram staining differentiates bacteria by the chemical and physical properties of their cell walls by detecting the properties of peptidoglycan. Gram negative bacteria after safranin or fuchsin staining will appear red or pink colour. Gram negative bacteria are later stained with safranin or fuchsin for observation under microscope. Those bacteria which retain the blue or purple colour of crystal violet are called Gram positive bacteria and those bacteria which loose the colour of crystal violet after washing with de-staining solution is called Gram Negative bacteria. Then the bacterial cells are treated with iodine solution (Lugol’s iodine) solution and washed with alcohol (de-staining solution). All bacterial cells will stain blue or purple colour with crystal violet solution. Bacteria are first stained with crystal violet or gentian violet. The two categories of bacteria based on gram staining are Gram positive bacteria and Gram negative bacteria. Christian Gram, a Danish Physician in 1884 developed a staining technique to distinguish two types of bacteria.
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