1. Bacterial Cytology &
Physiology
Bacterial Taxonomy
Parts of a bacterial cell
Specialized structures in bacteria

2. Taxonomical Ladder
x Kingdom Monera
x Phylum x Kingdom Plantae
x Class x Kingdom Animalia
x Order x Kingdom Protista
x Family x Kingdom Fungi
x Genus x Kingdom Monera
x Specie - Type &
Strain

5. New Classification:
x Carl Woese – based on cellular
organization (Domain above Kingdom)
x Bacteria– cell wall w/ peptidoglycan
x Archaea – cell walls, if present lack
peptidoglycan
x Eukarya – Protista, Fungus, Plants,
Animals

6. Characters used to classify
Bacteria
x Morphology- cell x Percentage of DNA
shapes & struc. base pairs
x Biochemistry & x DNA sequence
Physiology - condi- x DNA hybridization
tions & process x sequence of amino
x Serology - FAT & acids in proteins
slide agglutination x protein profiles
x Phage typing x sequence of rRNA

7. Prokaryote VS. Eucaryote

8. Procaryotes
x appendages: pili, x presence of
flagella, axial filaments plasma membrane
in spirochetes x undiff. cytoplasm
x Usually glycocalyx is x non-membrane
present bound organelles
x outer membrane present x 1 circular DNA
in gram (-)
x binary fission
x cell wall in all eubacteria
x 1 to few u

10. Eucaryotes
x different flagella from x cytoskeleton &
procaryotes
cytoplasmic streaming
x very few has x membrane bound
glycocalyx
organelles
x no outer memb. x paired chromosome
x no cell wall x mitosis & meiosis
x plasma membrane- x no endospores
phospholipid bilayer
x > than 10 u

12. Bacterial Cytology
x Structures external to the cell wall
x The cell Wall
x Structures internal to the cell wall
x General Structures
x Specialized structures

13. External to the cell wall:
x Glycocalyx – sugar coat
x Viscous, gelatinous polymer on the external of
the cell, composed of polysaccharide,
polypeptide or both
x Capsule – If Glycocalyx is organized and firmly
attached to the cell wall, capsule is formed
x Determines virulence of the cell
x Negative Staining

14. x Slime layer - If the substance is
unorganized & loosely attached to cell wall.
x EPS ( Extracellular polysaccharide ) –
x Glycocalyx made of sugar- enables the bacteria
to attach to various surfaces in the natural
environment in order to survive.
x Flagella/Flagellum ( whip )
x Long filamentous appendages that propel
bacteria

16. Arrangements of flagella:
x Monotrichous – single polar
x Amphitrichous – tuft at each end
x Lophotricous – 2 or more at one end
x Peritrichous – entire cell
x Atricous – no flagella
x Flagellar rotation depend on cells continuous
generation of energy
x Flagellar motion – run, swim, tumble, swarm

18. x Axial Filaments
x Unique in spirochetes, also called
endoflagella, which are bundles of fibrils
that arise at the ends of the cell beneath an
outer sheath and spiral around the cell.
x Propulsion causes spiral motion or
corkscrew movement

19. Fimbriae & Pili:
x Fimbriae/Fimbria
x can occur at the poles of the cell or evenly
distributed all over
x Functions for cell attachment/ in the
absence colonization cannot happen so no
disease ensues
x Pili/Pilus
x Longer than fimbriae, only 1 – 2 per cell
x Preparation for DNA transfer – sex pili

20. The Cell Wall
x Complex, semi rigid structure
responsible for the shape of the cell
x Composed of peptidoglycan (also
known as murein) made up of NAG ( N-
acetylglucosamine) and NAM (N-acetyl
muramic acid).
x Structures on the disaccharide portion is
repeating.

21. Gram + & - cell walls:
x Most gram (+) bacteria have many layers of peptidoglycan
in the cell wall forming a thick rigid structure while gram (-)
only contain 1 thin layer of peptidoglycan.
x Gram (+) contains teichoic acid consisting primarily of an
alcohol & phosphate
x Lipoteichoic Acid
x Wall teichoic Acid
x Gram (-) cell walls are susceptible to mechanical breakage
because they contain only small amount of peptidoglycan

22. Internal to the Cell Wall:
x Plasma Membrane/Bacterial Membrane
x Cytoplasm
x The Nucleus
x Ribosomes
x Inclusions
x Metachromatic granules
x Magnetosomes
x Endospores

23. Bacterial Membrane
x Functions: x Demonstrated by:
x osmosis & x Plasmolysis
permeability x Stain - Victoria
x cell division Blue
x primer for x Isolation - Diff.
biosynthesis centrifuge
x site of Ag x Ultrathin
determinant sections

27. Bacterial shapes &
arrangements
x Coccus - x Spirillus
x single, diplo,
x wavy, corkscrew,
tetrad, sarcinae,
comma-shaped
strepto , staphylo.
x Spiral bacteria may
x Bacillus -
have 1 or more
x single, diplo,
twists
strepto

28. Additional Shapes
x Star shaped cells – Genus Stella
x Rectangular flat cells – halophilic
Genus Haloarcula
x Triangular shaped cells

29. Basis of Shape:
x Shape of the bacterium is primarily
dependent on heredity.
x Generally bacteria are monomorphic,
maintain 1 single shape
x Due to environmental conditions, some
bacteria tend to become pleomorphic
which makes identification difficult. I.e.
Rhizobium & Corynebacterium

30. Trivia:
x Is coccobacilli a coccus or a bacilli?
Maybe both or neither of the two?
x Why do bacillus not have tetrads or
clusters?