Microorganisms - Small living organisms - Most ancient life form, 3.5 bya resembles modern cyanobacteria Stromatolites- produce O2 via photosynthesis- helped make earth atmosphere suitable for life Endosymbiosis- bacteria trapped in eukaryote cells

Fungi from eukaryote microbes protists (cytrids) Animals from eukaryote microbes flagellates (choanoflagellates) Plants from eukaryote microbes green algae (chlorophytes)

Importance - Recycle chemicals used in food chain - Control pollution- degrade oil and fuel spills - Used to make biofuel - Used to make food - Medicine

Scientists - Zacharias Janssen- first compound microscope - Robert Hooke- first to describe cells - Anton Van Leewenhoek- first to describe microbial cells

Diversity Systematics- study of evolutionary history of org. how taxa relate to each other Taxonomy- categorising how similar org based on morphological, molecular 5 Kingdoms: plant, Protista, fungi, animal, prokaryotes 3 domains: archaea, bacteria, eukarya

Organotroph- rely on organic compound for energy Lithotroph- don’t need organic compound for energy

Aquifex- most thermophilic, found in green sulfur bacteria, chemolithotrophic autotroph Thermotoga- anaerobic fermentative chemoorganotrophs, marine hydrothermal vents and hotsprings Thermodesulfobacterium- thermophilic, ether linked lipids, most thermophilic sulfate reducing bacterium Green non sulfure bacteria- anoxygenic phototrophy, chemoorganotroph, bacteriochlorophyll A & C Deinococci- tolerate heat and radiation, aerobic heterotroph, grow on sugar, amino acids and organic acids Thermus- taq polymerase isolates- used to replicate genes Cyanobacteria-oxygenic photosynthesis bacteria, fix co2, some diazotrophic Diazotrophic- convert atmospheric N to useful N Actinobacteria- gram positive, common soil bacteria, produce endospores, higher survival chance - Non sporulating lactobacillus - Endospore forming bacillus, clostridum - Cell wall less mycoplasmas - Coryneform and propanoic acid Corynebacterium, Arthrobacter - Actinobacteria mycobacterium - Filamentous actinobacteria streptomyces, actinomysis - Proteobacteria- largest phylum 5 groups: alpha, beta, gamma, delta, epsilon Spirochetes- common cause of disease, motile - Aerobic, microerophilic and anaerobic heterotrophs

Archaea Two major phyla: ▪ Euryarchaeota – Physiologically diverse group – Extreme thermophiles, halophiles, acidophiles – Marine group known only from environmental sequences ▪ Crenarchaeota  – Short branched group close to the base of the tree of life  – Mostly hyperthermophiles, but also cold dwelling marine environmental sequences known

Two additional phyla close to the base of the tree of life: – Korarchaeota ▪ Environmental sequences from hot springs – Nanoarchaeota ▪ Live attached to cells of Ignicoccus ▪ Very small cell and genome

- Hypersaline waters are coloured pink by the archaeon Halobacterium

Autrotrophs- use simple inorganic substances and light or chemical energy to synthesise food Heterotrophs- obtains energy through intake and digestion of organic substances Archaea- simple unicellular orgnaisms found in extreme environment Protists- unicellular eukaryotic microbes Algae- photosynthetic heterotrophs Fungi- non photosynthetic heterotroph eukaryotes, chitin cell walls Virus- acellular microbes

Aseptic Technique- transfer technique that minimise contamination of culture Anaerobic- don’t require oxygen for growth Microaerobic- require small amount of oxygen for growth

Prokaryotic Cell Cell wall- support and protect osmotic lysis Cytoplasmic membrane- permeability Ribosomes- site of translation Inclusions- storage of C, N, S, P compounds Nucleoid- formation of DNA in a single chromosome

Membrane - Bacteria: Lipid bilayer - Archaea: lipid monlayer - Lack sterol Functions - Permeability barrier- prevent leakage - Protein anchor- site of transport and chemotaxis, energy conservation Cell Wall - Shape and rigidity - Gram +ve – thick rough, single layer - Gram -ve – thin, smooth, multilayer - Archaea- thick Motility - Motile due to presence of one or more flagella Endospores - Some bacterial species produce endospores - Extremely resistant to heat, chemicals - Endosporium- thin, delicate, protein cover - Spore coat- layers of spore specific proteins - Coretex- loosely cross linked peptidoglycan - Core/ spore protoplast- contains cell wall, membrane

Fungi Exist as filamentous (mold), macroscopic (mushroom), unicellular (yeast) Groups: Chytridiomycota, Zygomycota, basidiomycota, ascomycota Hypha- filaments (mycelium group) - Separated by SEPTUM - Continuous growth for nutrient availability Conidia- asexual, commonly pigmented, dispersal Ascospore- sexual, produced in a sac Basidiospore- sexual, positive and negative Filamentous- large fruiting bodies

Nutrition (heterotroph) - Saprophytic- decomposers - Parasitic- feed directly on living animals/ plants - Symbiotic- live in living organisms without killing it

Digestion - Occurs outside the body - Secrete enymes - Degrade complex biopolymers

Reproduction - Asexual – spores - Sexual- positive and negative – fertilisation- meiosis Penicillium- conida spore, asexual Basidiomycota- basidium spores, sexual

Importance - Plant/ crop disease - Food and culture - Decomposition

Disease cycle - Inoculation- pathogen in contact with host - Attach and penetrate- hypha penetrate host tissue - Penetrate via: natural openings, plant wounds, enzymatic action

Enzymes: cellulose, hemicellulose, liginaise Medicine- secondary metabolites- compound produce by fungus not essential to the basic metabolism of fungus. 6/20 common prescription from penicillium

Infections- classified according to site of infection on body whether an opportunistic setting is necessary to establish disease. (mycoses) Superficial/ Cutaneous- infect outer layers of skin - Cause allergic response - Caused by dermatophytes- cannot invade living tissue Tinea (ringworm) - Corpus- ringworm of the body - Nigra/ manuum- palms - Capitis- head - Capitis- scalp - Pedis- foot - Cruris- groin - Unguium- nails - Candidiasis- vaginal Protista Eukaryotic - Earliest remains 1.2-1.5 bya - May have independently evolved as early as 2by after Archaea - Polyphyletic- evolved from evolutionarily distinct lineages - Larger than prokaryotic - Greater internal complexity - Specialised cell division method

Taxonomy- mostly unicellular eukaryotic microbes grouped in Protista - Plantae- multicellular, eukaryotic - Protista- eukaryotic, unicellular, multicellular - Animalia- multicellular, eukaryotic - Fungi- multicellular, eukaryotic - Eubacteria- unicellular, prokaryotic - Archaebacteria- unicellular, prokaryotic

Diplomonads- obligate human pathogens e.g. giardia- stomach infection Microsporidia- mainly animal parasites e.g. intestinal infection Trichomonas- anaerobic mitochondria, flagella processing e.g. trichomonas STD Trypanosomes- obligate parasites e.g. cause sleeping sickness Euglenoids- freshwater, motile, 2 flagella, photoreceptive eyespot Entamoeba- anaerobic human parasite e.g. amoebic dysentery Ciliates Paramecium- Ciliates Plasmodium- malaria Stramenopiles- diverse group- diatoms, brown algae, water mould Phaeophyta (brown)- multicellular, chlorophyll a/c, xanthophylls, cell wall- cellulose alginic acid Rhodophyta (red)- multicellular, chlorophyll a/d, cell wall- cellulose Chlorophyta (green)- uni/ multicellular, cell wall- cellulose, chlorophyll a/b Bacillariphyta (diatom)- unicellular, cell wall- pectin and silica, chlorophyll a/c, carotene, xanthophylls

Dinoflagellates- 2 flagella, most auto heterotrophs, marine symbionts, unicellular, plasma membrane, chlorophyll a/c, carotene Oomycota (water moulds)- multicellular, cell wall- cellulose, decomposers, chemoheterotrophic Slime moulds- amoeboid to plasmodia, form large fruiting bodies, release amoeboid cysts

Virus - Obligate intracellular parasite Virion - Intact particle (DNA or RNA) - Capsid- protein coat that can have glycoprotein/ lipid membrane - Protein receptors confer ability to infect host Evolution Regressive- small paracitic cell that lost genes not required for function overtime Cellular origin- virus evolved from segments of DNA or RNA that escaped the host genome (plasmid- DNA outside chromosomes) Co Evolution- virus arose from nucleic acids and proteins on early earth and evolved alongside cellular life History - Studies in late 1800’s using filters with small pore sizes -existence of small infective - Invention of electron microscope in 1931 allowed visualization viruses - First cultivation: