Bacteria 1
Ribosome
CytoplasmNucleoid
GlycocalyxCell wall
Cytoplasmic membrane
Flagellum
Inclusions
Prokaryotic Cell Structure
Chapters 3 and 11
Eukaryotic cell structure-- you should review from Biol 131
Archeal cell structure – not much different than Bacteria
Bacterial Classification-- you are not responsible for the details presented in Chapter 11, but should read about different types of bacteria presented in class
We will be discussing classification again as part of bacterial metabolism
Bacteria 2
Why are bacteria so small?Size affects ‘surface to volume’ ratio
Advantages of large S/V:diffusion ratesmetabolic ratesreproductive rates
Limits to size reduction?‘defective’ bacteria
Really big bacteria?-- Epulopiscium fishelsoni
Epulopiscium web sitehttp://www.micro.cornell.edu/cals/micro/research/labs/angert-lab/epulopiscium.cfm
Bacteria 3
Classification of bacteria is ‘murky’
A “Muddle in the Middle”Few distinctive characteristicsGenetically promiscuous
-- “horizontal” gene transfer
Traditional classification:anatomical featuresstaining characteristicsmetabolic properties
Newer approach
Genetic analysis
Bergey’s manual is the ‘Bible’
Bacteria 4
Classification based upon anatomical features
3 common shapes
-- coupled with staining propertiese.g., “Gram-pos cocci”“Gram-neg bacilli”
Some unusual shapes also:
Bacteria 5
Classification based upon anatomical features -- more info about these is in Chap 11
Other unusual bacteria
Spirochetes
Cell wall-less (mycoplasmas)
Stalked
Filamentous
Myxobacteria fruiting bodies Streptomyces
Bacteria 6
External Anatomical Structures-- Bacterial Flagella
Prokaryotic vs eukaryotic
Arrangementsmonotrichous
lopho-
amphi-
peri-
How do we know movementis rotational?
Flagella movement Flagella Details
Bacteria 7
How do flagellatedbacteria move?
‘Run and Tumble’ pattern
Bacterial movement
Chromatium motility
Bacteria 8
Spirochetes -- very strange structure-- e.g., Borrelia, Treponema
Axial filaments
Outer sheath
Motility
Spirochetes
Borrelia Movement
Bacteria 9
Fimbriae and Pili
Fimbriae adhesion to surfaces
Pili (pilus)genetic recombination
other functions?
Bacteria 10
The glycocalyx
FunctionsBiofilms -- adherence -- virulencePrevent desiccation
Composition
Capsule layersvs
Slime layers“xantham gum”(Xanthomonas)
S. Pneumo evasion
Bacteria 11
Cell wall structure
Hans Christian Gram -- 1884-- Crystal violet
Gram positive structure-- thick layer of peptidoglycan
Gram negative structure-- inner vs outer membranes-- thin layer of peptidoglycan-- lipopolysaccharides and endotoxins
Acid fast staining-- Mycobacterium
Lipopolysaccharide(LPS) layer
Outer membrane
Peptidoglycan
Cell membraneEffect of penicillin
Bacteria 12
Cell Membrane Structure
Review basic membrane structure from Biol 131
-- Phospholipid bilayers
-- Membrane proteins
-- Membrane fluidity
Membranes ofthermophilic archaebacteria
Bacteria 13
Components of prokaryotic cytosol
No membrane-bound organelles
Cytoplasm
Ribosomes
DNA
Inclusions
food or waste storage
Bacteria 14
Endospores
Clostridium & Bacillus
Formation and regrowth
Special properties?-- desiccated-- DNA binding proteins-- Ca-dipicolinic acid
Magnetotactic bacteria-- possess magnetosomes
Endospore formation
Magnetotactic Bacteria