Dr. Alvin Fox

Key Words Prokaryotic Outer membrane Eubacteria (Bacteria) Periplasmic space Archaebacteria (Archaea) Oxidative phosphorylation Eukaryotic Spheroplast/protoplast Plasmid Flagella Chromosome Chemotaxis Ribosome Axial filament Peptidoglycan (murein, mucopeptide) Periplasmic binding protein Gram stain Permeases Gram negative Storage Granules Gram positive Pili (fimbriae) Cell envelope Capsule (slime layer, glycocalyx) Cell membrane Endospore (spore) Cell wall

EUKARYOTES PROKARYOTES BACTERIA ARCHAEA

Prokaryotes (Bacteria) Eubacter "True" bacteria human pathogens clinical or environmental one kingdom Archaea Environmental organisms second kingdom

Eukaryotes Other cell-based life e.g. plants animals fungi

Prokaryotic Cell (versus Eukaryotic Cell) Not compartmentalized Cell membranes lack sterols (e.g. cholesterol) Single circular chromosome Ribosomes - 70S - subunits 30S (16S rRNA) 50S (5S & 23S rRNA)

Bacteria versus Archaebacteria Eubacteria peptidoglycan (murein) muramic acid Archaebacteria pseudomurein no muramic acid

Bacteria versus Archaebacteria 16S rRNA sequence different

Eukaryotic cell Prokaryotic cell Gram + Gram - (e.g. animal) Flagellum Nucleoid Rough endoplasmic reticulum Cell membrane Cell wall Nucleus Gram - Cell (inner) membrane Outer membrane Ribosomes Granule Cell wall Capsule Pili Cytoplasm Mitochondria

Plasmids Bacteria Extra-chromosomal DNA multiple copy number coding - pathogenesis factors - antibiotic resistance factors bacterial replication

The Cell Envelope Gram Stain Gram Positive Gram Negative

Oxidative phosphorylation occurs at cell membrane (since there are no mitochondria). Cell Wall Cytoplasm Cell membrane The cell wall is outside of cell membrane rigid, protecting cell from osmotic lysis.

GRAM POSITIVE GRAM NEGATIVE Lipoteichoic acid Peptidoglycan-teichoic acid Cytoplasmic membrane Cytoplasm GRAM NEGATIVE Lipopolysaccharide Porin Outer Membrane Braun lipoprotein Periplasmic space Inner (cytoplasmic) membrane Cytoplasm

Outer Membrane Gram negative bacteria major permeability barrier space between inner and outer membrane periplasmic space store degradative enzymes Gram positive bacteria no periplasmic space

GRAM NEGATIVE CELL ENVELOPE Outer Membrane (Major permeability barrier) Lipopolysaccharide Porin Braun lipoprotein Periplasmic space Degradative enzyme Periplasmic binding protein Permease Inner (cytoplasmic) membrane Cytoplasm

GRAM POSITIVE CELL ENVELOPE Degradative enzyme Peptidoglycan-teichoic acid Lipoteichoic acid Cytoplasmic membrane Cytoplasm

FLAGELLA Some bacteria are motile Locomotory organelles- flagella Taste environment Respond to food/poison chemotaxis

Flagella embedded in cell membrane project as strand Flagellin (protein) subunits move cell by propeller like action

Axial filaments spirochetes similar function to flagella run lengthwise along cell snake-like movement

Making Wall-less Forms Result from action of: enzymes lytic for cell wall antibiotics inhibiting peptidoglycan biosynthesis Usually non-viable Wall-less bacteria that don’t replicate: spheroplasts (with outer membrane) protoplasts (no outer membrane). Wall-less bacteria that replicate L forms

Naturally Wall-less Genus Mycoplasma

Pili (fimbriae) hair-like projections of the cell sexual conjugation adhesion to host epithelium

Capsules and slime layers outside cell envelope well defined: capsule not defined: slime layer or glycocalyx usually polysaccharide often lost during in vitro culture protective in vivo

Endospores (spores) Dormant cell Produced when starved Resistant to adverse conditions - high temperatures - organic solvents contain calcium dipicolinate Bacillus and Clostridium