micro

• Morphology - study of form and structure
• Spherical or Ellipsoidal - Round cells which multiply by binary fission and their arrangement depends on the plane of division.
• Diplococci – occur in pairs of cells
• Streptococci – cells arranged in beads or chains
• Staphylococci –irregular clusters resembling bunches of grapes.
• Tetrads – four cells arranged in a square along the same plane of division.
• Sarcinae – cuboidal arrangement of usually 8 or more cells along three dimensions.
• Cylindrical or Rod-Shaped - They do not have the variety of patterns exhibited by the cocci.
• Diplobacilli – occur in pairs
• Streptobacilli – occur in chains
• corynebacteria - display a palaside arrangement, they have a tendency to produce groupings of cells lined side by side like matchsticks.
• SPIRAL-SHAPED - These occur predominantly as unattached individual cells. Bacteria exhibit differences in:

    a. length

    b. number and amplitude of spirals

    c. rigidity of cell walls.
• Spirilla – are actual spirals or helices, like corkscrews. Their cell bodies are relatively rigid.
• Spirochetes – are spiral bacteria, but they differ from the spirilla in that they are able to flex and wriggle their bodies while moving.
• Vibrio/Comma Bacteria – short  incomplete spirals
• flagella – are thin, hairlike appendages protruding through the cell wall.
• Monotrichous – with one polar flagella. Ex: Vibrio cholera
• Amphitrichous– single flagellum at both ends. Ex: Alcaligens faecalis
• Lophotrichous – with tufts of flagella at both poles. Ex: spirilla
• Peritrichous - 8 or more flagella distributed over the surface. Ex: Samonella thyphoid
• Atrichous – bacteria which do not possess flagella. Ex: Staphylococcus spps.
• Antigenecity – the protein composition serves as the antigen and therefore elicit antibody specific for flagella
• Motility test - Directly observed by microscopic examination using wet mount and hanging drop technique.
• True Motile – if the bacteria seems to be going in a definite direction.
• Motile – growth of bacteria is away from the inoculation line.
• Nonmotile – growth of bacteria is close from the inoculation line
• Pili or Fimbriae - They  are shorter and finer than the flagella. They are seen in both motile and nonmotile bacteria, therefore they are not concerned with motility.
• Ordinary Pili – play a role in the adherence of symbiotic bacteria to host from cells.
• Sex Pili – responsible for the attachment of the donor cell and recipient cell in conjugation (Bridge bet. Bacterial cells for DNA transfer)
• Fimbria pilus - serves as a port of entry of genetic material during bacterial conjugation.
• Pili - used to transfer DNA from one cell to another
• Slime layer – masses of polymer which appear to be totally detached from the cells but entraps the cell. This structures gives a mucoid or viscous colony.
• Capsule - condensed, well-defined layer surrounding the cell made up from polysaccharide
• Glycocalyx – a loose meshwork of fibrils extending outward from the cell
• Peptidoglycan - ´Polymer of disaccharideN-acetylglucosamine (NAG) & N-acetylmuramic acid (NAM)´Linked by polypeptides
• Gram-positive - 80nm thick, composed mostly of several layers of peptidoglycan
• Peptidoglycan and Teichoic acid - Components of gram positive bacterial cell wall
• Cell wall teichoic acid - covalently linked with peptidoglycan
• membrane teichoic acid - covalently linked with membrane glycolipid and concentrated in mesosomes
• Gram-negative - consists of peptidoglycan, lipoprotein, outer membrane, and lipopolysaccharide.