Diversity of Life - Prokaryotes

What are prokaryotes? - a type of organism lacking a membrane-enclosed nucleus and membrane-enclosed organelles.

What are prokaryotes? - a type of organism lacking a membrane-enclosed nucleus and membrane-enclosed organelles. Bacteria

What are prokaryotes? - a type of organism lacking a membrane-enclosed nucleus and membrane-enclosed organelles. Bacteria Archaea

What are the features of prokaryotes? Look at: Cell surfaces Internal organization Nutritional/metabolic adaptations

What are the features of prokaryotes? Cell Surfaces -one feature which determines the kind of bacterium being dealt with -made up peptidoglycan Sugars (polymers) Polypeptides

What are the features of prokaryotes? Cell Surfaces -one feature which determines the kind of bacterium being dealt with peptidoglycan layer plasma membrane Cell wall = peptidoglycan layer

What are the features of prokaryotes? Cell Surfaces -one feature which determines the kind of bacterium being dealt with lipopolysaccharide Outer membrane peptidoglycan layer plasma membrane Cell wall = peptidoglycan layer Cell wall = peptidoglycan layer + outer membrane

What are the features of prokaryotes? Cell Surfaces -one feature which determines the kind of bacterium being dealt with lipopolysaccharide Outer membrane peptidoglycan layer plasma membrane Cell wall = peptidoglycan layer Cell wall = peptidoglycan layer + outer membrane Gram positive Gram negative

What are the features of prokaryotes? Gram positive Gram negative

What are the features of prokaryotes? Cell surfaces and infection -lipopolysaccharide layer - can produce toxins -outer membrane - protects bacteria from host’s immune system - outer membrane - protects bacteria from antibiotics

What are the features of prokaryotes? Internal structure cell wall nucleoid region plasmids plasma membrane ribosomes capsule chromosome Prokaryotic cell

What are the features of prokaryotes? Internal structure - what do the structures do? Cell wall - provides physical protection, maintains shape in different salinities Capsule - sticky, polysaccharide or protein - protection from host’s immune system Plasma membrane - acts as a selective chemical barrier Chromosome - a ring of DNA that carries all the necessary genetic information Nuceloid region - area of the cell containing the chromosome Plasmids - small rings of DNA - function in ‘emergency’ situations Ribosomes - site of protein synthesis in the cell

What are the features of prokaryotes? Nutritional and metabolic adaptations Ways of obtaining energy Autotroph - use only CO2 as a carbon source Heterotroph - need one organic nutrient (e.g. glucose) Phototrophs - use light as a source of energy Chemotrophs - use chemicals as a source of energy

What are the features of prokaryotes? Nutritional and metabolic adaptations Ways of obtaining energy Energy Carbon Mode of nutrition source source Autotrophs Photoautotroph Light CO2 Chemoautotroph Inorganic CO2 chemicals Heterotrophs Photoheterotroph Light Organic compounds Chemoheterotroph Organic Organic compounds compounds

What are the features of prokaryotes? Nutritional and metabolic adaptations Relationship to Oxygen Facultative Obligate None Need O2 for cellular respiration Use O2 for cellular respiration but can grow without it Poisoned by O2 -use other chemicals Aerobes Anaerobes

What are the features of prokaryotes? Nutritional and metabolic adaptations Relationship to Nitrogen N2 NH3 Amino acids Proteins Plant can’t fix N2

Classification of Prokaryotes What features separate the Bacteria from the Archaea? Characteristic Bacteria Arachaea Peptidoglycan yes no Reponse to growth growth antibiotics inhibited not inhibited Growth above no some species 100ºC See Table 27.2 in your book

Classification of Prokaryotes Alpha Beta Proteo- bacteria Gamma Delta Epsilon Chlamydias Spirochaetes Cyanobacteria Gram positive bacteria Archaea

Classification of Prokaryotes Alpha Gram positive Beta Gram negative Proteo- bacteria Gamma Delta Epsilon Chlamydias Spirochaetes Cyanobacteria Gram positive bacteria Archaea

Classification of Prokaryotes Alpha Proteobacteria -e.g. Rhizobium - nitrogen fixing in plant roots Beta Proteobacteria -several soil bacteria Gamma Proteobacteria -some pathogens - Salmonella (food poisoning) Legionella (Legionnaire’s disease) Vibrio cholerae (Cholera) Delta Proteobacteria -several soil bacteria Epsilon Proteobacteria -gastrointestinal infections

Classification of Prokaryotes Chlamydias -venereal disease

Classification of Prokaryotes Chlamydias -venereal disease Spirochaetes -disease organisms Treponema pallidum - syphillus Borrelia burgdorferi - Lyme disease

Classification of Prokaryotes Gram positive Bacteria -very diverse group Some familiar ones: Streptomyces - antibiotic production

Classification of Prokaryotes Gram positive Bacteria -very diverse group Some familiar ones: Streptomyces - antibiotic production Bacillus anthrax - anthrax

Classification of Prokaryotes Gram positive Bacteria -very diverse group Some familiar ones: Streptomyces - antibiotic production Bacillus anthrax - anthrax Streptococcus - respiratory disease

Classification of Prokaryotes Cyanobacteria - only prokaryotes with plant-like photosynthesis

Classification of Prokaryotes Archaea - differ from bacteria in several ways but have no peptidoglycan Common in extreme conditions Thermophiles - live at extreme temperatures (>100ºC) Pyrolobus -in deep sea vents

Classification of Prokaryotes Archaea - differ from bacteria in several ways but have no peptidoglycan Common in extreme conditions 2. Halophiles - live at extreme salinities

Classification of Prokaryotes Archaea - differ from bacteria in several ways but have no peptidoglycan Common in extreme conditions 3. Methanogens - use CO2 to oxidize H2 - release CH3 - “swamp gas”