microbiology cell biology of bacteria northland community & technical college instructor terry...

MICROBIOLOGY

Cell Biology of Bacteria

Northland Community & Technical College

Instructor

Terry Wiseth

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BACTERIAL FACTS

Scientists have named and described more than 4,000 species of bacteria

New ones are discovered so rapidly, however, they estimate the number of unknown species in the millions

Almost every time scientists search among bacteria in a soil or water sample, they discover previously unknown species

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The overwhelming majority of bacteria are harmless to humans or animals

Bacteria get virus infectionsAntibiotics and other bacteria-derived

materials are the basis of a $50 billion annual market for biotechnology products

Oil spills are cleaned primarily by bacteria that feed on oil

BACTERIAL FACTS

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About 10 percent of human body weight and 50 percent of the content of the human colon is made up of bacteria (Escherichia coli)

each square centimeter of human skin hosts an average of 100,000 bacteria

Washing removes many, but they reproduce so quickly--doubling every 20 minutes--that the population is restored in hours

BACTERIAL FACTS

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So many bacteria live underground that their total weight has been estimated at 100 trillion tons

If these microbes were spread over Earth's land surface, they would make a layer five feet thick

BACTERIAL FACTS

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CLASSIFICATION

Microbesorganisms smaller than the eye

can detectbacteriafungiprotistsvirus

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CELL TYPES

ProkaryotesEukaryotes Viruses

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PROKARYOTES

Monerabacteria1

micron diameter

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EUKARYOTESalgae, protozoa

and fungi5 - 100 microns

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VIRUSES

neither prokaryotes nor eukaryotes informational parasiteseach kingdom has its own

associated viruses

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MICROBIAL SIZE

Virus 0.05 to 0.1 microns

Bacteria 0.5 to 1.5 microns

Red blood cell 5 microns

Sperm 60 microns

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MICROBIOLOGY

disease

agriculture

food and drink

chemical products

basic research

biotechnology

PROKARYOTESVS

EUKARYOTES

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CELL CHARACTERISTICSProkaryote Eukaryote

Chromosome Single circular

ChromosomePaired linear

Chromosome locationNucleoid(no membrane)

Chromosome locationNucleus(membrane present)

Nucleolus Absent Nucleolus Present

Extra chromosomalDNA in Plasmid

Extra chromosomalDNA in Mitochondriaand Chloroplast

Cellular Respiration in Cell membrane

Cellular Respiration in Mitochondria

Locomotion Rotating flagella

Undulating flagella,cilia, amoeboidmovement

Ribosome incytoplasm

Ribosome inorganelles

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BACTERIAL SHAPE

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BACTERIA SHAPE

range in size from 0.20 to 2.0 micrometers in diameter1) Bacillus2) Spiral3) Cocci

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BACILLUS

1) Bacillus Rod shape

Diplobacilli Two bacilli together

Streptobacilli Chains of bacilli

Vibrioscurved rods

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BACILLUSEscherichia coli

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SPIRAL

2) Spiral spirillia

Spiral, helical, corkscrew shape that is rigidrigid

spirochetethe organism is flexibleflexible and

undulating

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COCCI

3) Coccispherical shaped

diplococciremain in pairs

streptococcichains

staphylococciclusters

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COCCI

Moraxella catarrhallis

inhabitant of the upper respiratory tract, especially the nasal cavity

notice some are in the diploid state

BACTERIALCELL WALL

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CELL MEMBRANE

phospholipid bilayer integral and peripheral proteins

embeddedmaintains the selective

permeability of the cellhas respiratory enzymes

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CELL WALLcell wall surrounds the cell membraneStructurally, the wall is necessary for

1) maintain shape2) counter osmotic pressures3) attachment sites for

bacteriophages4) platform for surface appendages

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CELL WALL1) Maintaining the cell's

characteristic shapethe rigid wall compensates for the flexibility of the phospholipid membrane and keeps the cell from assuming a spherical shape

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CELL WALL2) Countering the

effects of osmotic pressurethe strength of the wall is responsible for keeping the cell from bursting when the intracellular osmolarity is much greater than the extracellular osmolarity

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CELL WALL3) Providing

attachment sites for bacteriophagesteichoic acids attached to the outer surface of the wall are like landing pads for viruses that infect bacteria

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CELL WALL4) Providing a rigid platform for

surface appendagesflagella, fimbriae, and pili all emanate from the wall and extend beyond it

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CELL WALLcell walls of all bacteria are not identicalcell wall composition is one of the most

important factors in bacterial species analysis and differentiation

clinicallycontributes to ability to cause diseasesite of action of antibiotics

There are two major types of walls: Gram-positive Gram-negative

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GRAM POSITIVE

Has a thick peptidoglycan layer90% of the Gram-positive cell

wall is comprised of peptidoglycan

two types of teichoic acidsteichoic acids

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GRAM POSITIVE1) Lipoteichoic acid

on the surface, embedded in the peptidoglycan layer

linked to the cytoplasmic membrane

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GRAM POSITIVE

2) Wall teichoic acid on the surface linked to only the peptidoglycan

layer

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GRAM POSITIVE

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cell wall of Gram-negative bacteria is much thinnercomprised of only 20%

peptidoglycanhave two unique regions which

surround the outer plasma membrane: periplasmic space lipopolysaccharide layer

GRAM NEGATIVE

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GRAM NEGATIVE

a thin peptidoglycan layer an outer membrane attached to the

peptidoglycan layer by lipoproteins

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GRAM NEGATIVE

the outer membrane is made of protein, phospholipid and lipopolysaccharidethe lipid portion is embedded in

the phospholipidThe lipid is toxic

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GRAM NEGATIVE

The cell wall has channels called Porins for the transport of low molecular weight substances

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GRAM NEGATIVE

periplasmic space between the cytoplasmic membrane and the cell wall hydrolytic enzymesantibiotic inactivating enzymes

transport proteins

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Strong negative charge assists in:evading phagocytosisevade the complement system

provides increased barrier to:antibiotics, lysozymes,

detergents

GRAM NEGATIVE

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provides more attachment sites for:virusharmful substances

more susceptible to mechanical breakage

lipid A endotoxin is toxic to host

GRAM NEGATIVE

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CELL WALLthe cell wall is not a

regulatory structure like the cell membrane

though it is porous, it is not selectively permeable and will let anything pass that can fit through its gaps

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EXTRACELLULAR MATRIX

attached to the cell wall made of polysaccharide or

polypeptide, or a combination of both

form a viscous layercapsuleslime layer

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CAPSULECapsule

thick, structured and adheres strongly to the cell wallAdhere to surfaces to form coloniesAntiphagocyticAntigenicProtect the organism from dehydration

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CAPSULE

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SLIME LAYERSlime layer

disorganized and loosely attached to the cell wallStaphylococcus mutans

causes dental caries

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MOVEMENTFlagellum

Made of the protein flagellinrotation is for swimming towards an

attractantwater is as viscous as syrup for a bacteriaable to move 50 microns/sec

100X bacterial body length/secfish able to swim only 10X body length/sec

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MOVEMENTAxial Filaments

found in Spirochetes similar to flagellaattached throughout the body

length

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PILImade of the protein pilin virulence factors project from the cell surfaceConjugation Pili

for the transfer of extrachromosomal DNA between donor and recipient

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FIMBRIAE

used for attachment to surfacesmore numerous than pili

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CYTOPLASMIC STRUCTURESNucleoid

area of concentrated DNA

no nuclear membrane

The DNA is single circular

double stranded without proteins

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CYTOPLASMIC STRUCTURESRibosomes

cytoplasmic, not attached to organelles

Plasmids Extrachromosomal loops of DNA

some code for drug resistancetoxins

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TYPICAL BACTERIA

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ENDOSPORES

Metabolically inactivemay produce endospores under

environmental stresslack of waterlack of nutrients severe temperature changes

Clostridium Bacillus

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ENDOSPORESSpores can be dormant for many

yearscan survive

extreme heatdesiccationradiationtoxic chemicals

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ENDOSPORES

when conditions become favorable they revert to an active state

Spore germination is activated by heat in the presence of moistures

END CELL BIOLOGY OF

BACTERIA

microbiology cell biology of bacteria northland community & technical college instructor terry...

Documents

plasmidextra chromosomal

amoeboid movementribosome

bacteriaderived materials

human colon

percent of human body

number of unknown species

total weight

species of bacterianew