Micropara-Lab

• Bacteria are metabolically active unicellular organisms that have cell walls but lack organelles and an organized nucleus, which divide by binary fission. These microbes contribute to disease pathogenesis.
• Bacteria Size


  • Spheres measurement usually ranges from about 0.2 um in diameter to 10.0 um-long spiral-shaped bacteria, to even longer filamentous bacteria
  • Average coccus is about 1 um in diameter
  • Average bacillus is about 1 um wide -3 um long
  • Bacteria range in size from 0.2 to 5 micrometers
  • Mycoplasma, the smallest microbe, is comparable in size to poxviruses (largest viruses) and may survive without a host
  • The longest bacterium rods are 7 um in size, similar to yeasts and human red blood cells
• Bacteria Reproduction


  1. Mitosis (Identical daughter cells) by binary fission - bacteria divide, one cell splits in half to become two daughter cells

  2. The time it takes for one bacterial cell to split into two cells is referred to as that organism's generation time
• Bacteria Basic Shapes


  • Spherical (cocci)
  • Rod-shaped (bacilli)-cylindrical
  • Spiral-shaped (spirilli/spirilla)- can be gently curved or corkscrew like. Rigid and capable of movement
• Varieties of Cocci


  • Diplococci (cocci that divide and remain attached in pairs)
  • Streptococci (rods that remain attached in chains after cell division)
  • Staphylococci (cocci in a grapelike cluster or broad sheet)
  • Tetrad (a group of four cocci)
  • Sarcina / Octad (a group of eight bacteria that remain in a packet after dividing)
• Varieties of Bacilli


  • Coccobacilli (oval rod)
  • Diplobacilli (rods that divide and remain attached in pairs)
  • Streptobacilli (rods that remain attached in chains after cell division)
  • Palisade (bacilli stack up next to each other, side by side)
• Varieties of Spirilum


  • Vibrio (short curved rod and comma shaped with less than one turn or twist in cell)
  • Spirochetes (have a helical shape, flexible, with an axial filament which helps in motility)
  • Spirilla (helical-shaped/corkscrew form, have a flagellum but lack the endoflagella)
• Other Shapes and Arrangements

  • Appendaged Bacteria (produce a distinct structure such as pillus or fimbriae)
  • Pleomorphic Bacteria (do not have a defined form, can alter shape)
  • Filamentous Bacteria (filament-shaped, long and thin, sometimes divide to form branches)
  • Club-shaped Rod Bacteria (thinner on one side than the other)
  • Box-shaped/Rectangular Bacteria (nonpathogenic)
  • Triangular shaped Bacteria (live on saline environments)
  • Stalked Bacteria (possess a stalk on one end of the cell)
  • Star-shaped Bacteria (found in freshwater, soil, and sewage)
• Glycocalyx (Slime Layers and Capsules)


  • Thick layer of material outside the cell wall, outermost covering of some bacteria
  • Capsule - An outer, viscous and gelatinous covering on some bacteria composed of a polysaccharide or polypeptide, highly organized and firmly attached to the cell wall, serves as antiphagocytic infection, protects the encapsulated bacteria from being phagocytized by phagocytic WBC, indicative of virulence or degree of pathogenicity
  • Slime layer - part of the glycocalyx that is unorganized and loosely attached to the cell wall, allows bacteria to slide or glide along solid surfaces, mediates adherence to surfaces
• Cell Wall (Murein Sacculus)


  • The outermost component of all bacteria (except Mycoplasma species)
  • Peptidoglycan, also known as murein, is a polymer that forms a mesh-like peptidoglycan layer, creating the cell wall
  • Murein represents a type of bacterial exoskeleton known as murein sacculus, that completely surrounds the cell
  • Function of cell wall is to provide rigidity, strength, and protection
• Gram-Positive Cell Wall


  • Thick/Multilayered
  • Teichoic acids - for attachment and crucial in cell shape determination, cell division regulation and other aspect of gram positive bacteria
  • Polysaccharides - Carbohydrate consisting of many sugar units, e.g. glycogen, cellulose, and starch
• Gram-Negative Cell Wall


  • Thin Monolayered
  • Outer membrane - gram negative cell wall has presence of a plasma membrane located outside of the peptidoglycan layers
  • Lipoprotein (responsible for endotoxin production) - these are large molecules known as lipopolysaccharide (LPS), which are anchored into the outer membrane and project from the cell into the environment. LPS is made up of three different components: O-antigen or O-polysaccharide, core polysaccharide, and Lipid A
  • Periplasmic Space - The space between the plasma membrane and outer membrane of Gram-negative cell wall, fluid filled space between outer membrane and cytoplasmic membrane, has enzymes for breakdown of large molecules and transports protein for regulation of osmolality of cells, site of action of some antibiotics that destroy peptidoglycan or inhibit its synthesis
• Cell Membrane (Cytoplasmic Membrane)


  • Located beneath the cell wall, encloses the cytoplasm of the cell
  • Selective permeable - The property of a plasma membrane to allow certain molecules and ions to move through the membrane while restricting others
• Cell Structures - Projecting Structures

  • Pili or Fimbriae (appendages on a bacterial cell used for attachment)
  • Flagellum (whip-like structure for motility, enables cell to swim through liquid environments, movement toward or away from a particular stimulus is called taxis)
  • Axial Filament (two flagella like fibril structure for motility found in spirochetes, allows them to move in a spiral, helical, or inchworm manner)
• Cell Structures - Internal Structures

  • Nucleoid (region containing the chromosome)
  • Mesosomes (extensions of the cell membrane present in cytoplasm as infolding, serve in DNA replication and guide distribution of duplicated bacterial chromosomes)
  • Ribosomes (tiny spherical organelles that make proteins, target site of some antibiotics)
  • Granules or Inclusion Bodies (storage vessels, e.g. glycogen)
  • Endospores (resting structure formed inside some bacteria, allows survival in extreme conditions)
  • Cytoplasm (semi-fluid gelatinous nutrient matrix where organelles are suspended)
• Culture Media


  • Liquid Media (broth, milk, infusion, does not solidify)
  • Semi-Solid Media (clot-like consistency, solidifying agent like gelatin/agar, thickens but not firm)
  • Solid Media (firm surface, for culture of bacteria and fungi, can be liquefiable and non-liquefiable)
  • General Purpose Media (to grow and support broad spectrum of microbes, contains basic nutrients)
  • Enrichment Media (for selected/desired microorganisms, uses blood, serum, or growth factors)
  • Selective Media (used to grow a 'selected' microorganism, prevents other organisms from growing)
  • Differential Media (allows for growth of several types of microorganisms to show differences)
• In order to grow, bacteria need a source of raw materials and energy. Source can be the same (e.g. glucose) or different (e.g. CO2 and sunlight). Bacteria can't grow on nothing.
• Aseptic technique must be used throughout the entire process, including preparation of media and transferring cultures.
• The purpose of the experiment is to determine if there are any differences between the two samples.
• NITO

  LEGULE NICOLE
• Cocci

  Spherical bacteria
• Bling

  Rod: 0-> Pababa
• MICROBIOLOGY AND PARASITOLOGY
• WEEK 2
• BACTERIAL MORPHOLOGY
• Bacteria

  • Metabolically active unicellular organisms
  • Have cell walls but lack organelles and an organized nucleus
  • Divide by binary fission
  • Contribute to disease pathogenesis
• Bacteria Size

  • Spheres measurement usually ranges from about 0.2 um in diameter to 10,0 um-long spiral-shaped bacteria, to even longer filamentous bacteria
  • Average coccus is about 1 um in diameter
  • Average bacillus is about 1 um wide-3 um long
  • Range in size from 0.2 to 5 micrometers
  • Mycoplasma, the smallest microbe, is comparable in size to poxviruses (largest viruses) and may survive without a host
  • The longest bacterium rods are 7 um in size, similar to yeasts and human red blood cells
• Bacteria Reproduction

  1. Mitosis (Identical daughter cell)

  2. Binary fission-bacteria divide; one cell splits in half to become two daughter cells

  3. Generation time - the time it takes for one bacterial cell to split into two cells
• Bacteria Basic Shapes

  • Spherical (cocci)
  • Rod-shaped (bacilli)
  • Spiral-shaped (spirilli/spinilla)
• Spiral-shaped bacteria

  • Can be gently curved or corkscrew like
  • Rigid and capable of movement
• Morphologic Arrangements of Bacteria

  • Diplococci (cocci in pairs)
  • Streptococci (cocci in chains)
  • Staphylococci (cocci in grape-like clusters)
  • Tetrad (group of 4 cocci)
  • Sarcina/Octad (group of 8 cocci)
  • Coccobacilli (oval rods)
  • Diplobacilli (rods in pairs)
  • Streptobacilli (rods in chains)
  • Palisade (bacilli stacked side by side)
• Varieties of Spirilla

  • Vibrio (short curved rods)
  • Spirochetes (helical shape, flexible with axial filaments)
  • Spirilla (helical/corkscrew shape, rigid with flagella)
• Appendaged Bacteria

  • Produce distinct structures like pili or fimbriae
  • More virulent
• Appendaged Bacteria

  • Neisseria gonorrhoeae
• Pleomorphic Bacteria

  • Bacteria that do not have a defined form
  • Can alter shape, but in pure culture they appear to have a definite form
• Pleomorphic Bacteria

  • Mycoplasma pneumoniae
  • Mycoplasma genitalium
• Filamentous Bacteria

  Filament-shaped bacteria that are long and thin, divide to form branches resembling strands of hair or spaghetti (mycelium)
• Filamentous Bacteria

  • Actinomyces
• Club-shaped Rod Bacteria

  Thinner on one side than the other
• Club-shaped Rod Bacteria

  • Corynebacterium