Prokaryotic Form and Function
-the way their DNA is packaged
-makeup of their cell wall
-their internal structure
ALL Bacteria Cells
-cell membrane
-cytoplasma
-ribosomes
-cytoskeleton
-usually 1 chromosome
Most Bacteria Cells
-a cell wall
-a surface coating called a glycocalyx
Some but not all Bacteria Cells
-flagella, pili, fimbriae
-an outer membrane
-plasmids
-inclusions
-endospores
-intracellular membranes
Prokaryotes (unicellular organisms)
-maintain their shape
-sometimes they can act as a group, in colonies, or in biofilms
Prokaryotic (measurement)
measured about 1 mm
-can range from .05-.2 mm to 750 mm
Prokaryotic (shape and size)
-this is plemorphism caused by variation in cell wall structure or absence of cell wall
Pleorphic Genera
-mycoplasma
-rickettsia
chalmydia
-corynebacterium
-haemophilus
Flagella
-bacterial locomotion
-3 distinct parts
-compromised of many proteins
-360 rotation
Monotrichous
single flagellum
lophptrichpous
small bunches of flagella pole
Amphitrichous
flagella at both poles of the cell
peritrichous
flagella dispersed randomly over the surface of the cell
Bacterial Movement
-bacteria move in response to chemical signals
-receptors bind extracellular molecules, which triggers flagellum to rotate
Runs
smooth linear movement toward a stimulus
Tumbles
flagellar rotation reverses, causing the cell to stop and change its course
Fimbriae
used for attachment
pili
used for attachment and exchange during conjugation
Glycocalyx
-composed of polysaccharides, proteins, or both
-varies in thickness (slime layers or capsule)
-used to avoid phagocytosis and for adhesion
Cell Envelope
-lies outside of the cytoplasm
-composed of 2 or three basic layers
-outer membrane, cell wall, cell (plasma, cytoplasmic) membrane
Peptidoglycan Cell Wall
-repeating framework of long glycan chains cross linked by short peptide fragments
-present in most bacteria
-provides strength to resist rupturing due to osmotic pressure
Gram Positive Cell
-thick peptidoglycan
-telchoic acid, lipoteichoic acid
-1 membrane: the cell membrane
-if you destroy cell membrane you destroy ATP production
Gram Negative Cell
-thin peptidoglycan
-lipopolysaccharide
-2 membranes
porins
Acid Fast bacteria
-mycobacterium and nocardia spp.
-contain my colic acid (wax)
-modified gram-positive structure
-must use the acid fast stain to identify pathogens causing tb and leprosy
Cell Wall Deficient Bacteria
-cell membrane stabilized by steroids, is resistant to lysis
-other cell wall types called l forms are linked to certain infections
-chemical treatment: lysozyme or penicilin
Lipopolysaccharide
-located in the outermost layer of the outermsmbrane
-in gram negative cell
-lipid a stimulates fever and shock
Cytoplasmic Membrane
-a lipid bilayer with proteins embedded
-contain phospholipids and proteins
-provides a site for metabolic reactions
-respiration and ATP synthesis, lack of mitochondria
-regulate the passage of nutrients into and out of cell
Cytoplasm
-70-80% water
-soluble proteins, salts, and carbs
-site of many chemical reactions
-nucleoid: location of DNA
bacterial DNA
-dna is most bacteria exists in form of a single circular bacterial chromosome
-many bacteria contain other nonessential extrachromosomal dan called plasmids
Svedberg Unit
a unit to measure to assess how fast molecules move in a centrifuge
Ribosomes
-total size is 70s
-60% rRna and 40% protein
-translates mRNA into proteins
Storage Bodies
-non-membrane bound granules
-usually for storage of nutrient
Cytoskeleton
-peptidoglycan layer determines shape of many bacteria
-others use protein fibers composed of actin and tubulin to alter cell shape
Endospores
-dormant bodies associated primarily with bacillus and clostridium spp
-heat resistance due to ca and dipicolinic acid content
-cortex, spore coats protect against radiation and chemicals
-when spores of clostriu/b are embedded in a wound with dead tissue
Botulism
food poisoning
Gangrene
infection of body, destruction of tissue
Tetanus
lock jaw
Archaea
-many are found in extreme environments
-different from members of bacteria and eukarya in terms of cell structure, metabolism, genetics
Bergy's Manual of Determinative Bacteriology
-phenotypic data
-for studying prokaryotic relationships and origins
-organizes into four major divisions based on cell wall structure
Bergy's Manual of Systemic Bacteriology
rRNA sequencing data
Gracilicutes
gram negative cell walls
-thin skined
Firmicules
gram positive cell walls
-thick skinned
Tenericules
lack a cell wall
-soft
Mendosicules
archaea with unusual cell walls
Species
-theoretically a collection of bacterial cells, all of which share an overall sim. pattern of traits and 70-80% of their genes
-members are given species can show variations
Variations of Species
-subspecies, strain, type are terms used to designate bacteria of the same species that have diff. characteristics
serotype
representatives of a species that stimulate a distinct pattern of antibody responses in their hosts