2. CLASSIFICATION
Microorganism are grouped under 2
I. Prokaryotes (Bacteria & Blue-green algae)
II. Eukaryotes (Fungi, Parasites, other algae)
Viruses are neither prokaryotes nor
eukaryotes as they lack the characteristics of
living thinks except replication.
3.
4.
5. SIZE
• Bacteria size in micrometer and virus size in
nanometer
• Bacteria observed by light microscope and
Viruses observed by electron microscope
• To see microorganisms – staining is used
6. MORPHOLOGY OF BACTERIA
• Depending on their shape;
Cocci- oval/spherical cells
Bacilli- rod shaped
• Arrangement;
Singles Pairs
Chains clusters
• Based on gram staining property;
Gram positive
Gram negative
13. FUNCTIONS OF CELL WALL
Maintaining the cells characteristic shape
Providing a rigid platform for surface appendages- flagella,
fimbriae/pili all emanate from the wall and extend beyond it.
Providing attachment sites for bacteriophage
Be the sites of major antigenic determinant of cell surface-
endotoxcity
Site of action of many antibiotics & resistance
17. MESOSOMES / Chondroids
• Vesicular/convoluted/multilaminated
• More prominent in G+.
• LOCATION:
Often found next to septa, in dividing
bacteria or seen attached to nuclear body.
• FUNCTION:
Site of bacterial respiration
18. INTRACYTOPLASMIC INCLUSIONS
• Storage sites for nutrients/energy.
• Formed under nutritional deficiency conditions & disappear in
the presence of excess nutrients
Staining
Toluidine blue, Neisser, Albert, Acid-fast, wet films
Electron microscopy
19. VACUOLES
• Vacuoles are fluid containing cavities
• Separated from cytoplasm by a membrane
• Function - uncertain
20. NUCLEOID
• Genetic material arranged in irregular shape
• Oval, Elongated
• Have no nuclear membrane
• Seen by Electron Microscope
Plasmid
Extrachromosomal ds circular DNA.
Not essential for life.
Present singly or in multiple numbers.
Episomes- when integrated with chromosomal DNA.
Drug resistance and toxigenicity