Transcript Simple Bacterial Cell

Classification
• Old 5 Kingdom system
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Eukaryote
Prokaryote
Monera
Protists
Plants
Fungi
Animals
• New 3 Domain system
• Bacteria
• Archaebacteria
• Eukaryotes
– Protists
– Plants
– Fungi
– Animals
Archaebacteria
&
Bacteria
Prokaryotes
Domain Bacteria
Domain Archaebacteria
Domain
Bacteria
Domain
Archaea
Common ancestor
Domain
Eukarya
Simple Bacterial Cell
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Prokaryote cell COMPOSITION!
Macromolecule
Primary Subunits
Proteins
amino acids
Polysaccharides
Flagella, pili, cell walls, cytoplasmic
membranes, ribosomes, cytoplasm
sugars (carbohydrates)
Phospholipids
fatty acids
Nucleic Acids
nucleotides
(DNA/RNA)
Where found in cell
capsules, inclusions (storage), cell walls
membranes
DNA: nucleoid (chromosome), plasmids
rRNA: ribosomes; mRNA, tRNA: cytoplasm
Prokaryote cell Structure
• Unicellular
– bacilli, cocci, spirilli
• Size
– 1/10 size of eukaryote cell
• 1 micron (1um)
• Internal structure
– no internal compartments
• no membrane-bound organelles
• only ribosomes
– circular, naked DNA
• not wrapped around proteins
Morphology
Cocci –
Staph aureus
Bacillus –
Bacillus anthracis
Spirilla Borrelia burgdorferi
“department of redundancancy
department” – more “mor”phology
Staining Characteristics
Gram +
Gram –
Stains according to the thickness of the peptidoglycan layer!
Prokaryote Cell Wall Structure
Gram-positive bacteria
peptide side
chains
cell wall
peptidoglycan
plasma membrane
protein
peptidoglycan = polysaccharides + amino acid chains
lipopolysaccharides = lipids + polysaccharides
Gram-negative bacteria
cell wall
outer membrane of
lipopolysaccharides
outer
membrane
peptidoglycan
plasma
membrane
Prokaryotic metabolism
• How do bacteria acquire their energy & nutrients?
– autotrophs
• acquire carbon from inorganic sources(CO2)
– phototrophs
• photosynthetic bacteria
– chemotrophs
• oxidize inorganic compounds/chemicals
– nitrogen, sulfur, hydrogen…
– heterotrophs
• live on plant & animal matter
• decomposers & pathogens
Bacteria as beneficial (&
necessary)
• Life on Earth is dependent on bacteria
– decomposers
• recycling of nutrients from dead to living
– nitrogen fixation
• only organisms that can fix N2 from atmosphere
– needed for synthesis of proteins & nucleic acids
– plant root nodules
– help in digestion (E. coli)
• digest cellulose for herbivores
– cellulase enzyme
• produce vitamins K & B12 for humans
– produce foods & medicines
• from yogurt to insulin
Genetic variation in bacteria
• Mutations
– bacteria can reproduce every 20 minutes
• binary fission
– error rate in copying DNA
• 1 in every 200 bacteria has a mutation
• Genetic recombination
– bacteria swap genes
• plasmids
– small supplemental
circles of DNA
The END!!!!!!!
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