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Life • Individual survival – Take in, digest nutrients – Eliminate wastes – Recognize self from non-self – Recognize enemies – Repair damage • Reproduction – Survival of species – Gene transfer US Vertebrates Invertebrates Plants Animals Archaea Bacteria UCA Prokaryotes Single-celled Protozoa Eukaryotes Algae Fungi Cell Functions • Maintenance – Recovery of energy from nutrients – Storage of energy – Synthesis of correct proteins and other cell components • Perpetuation of self – DNA replication – Cell division • Specialized functions – e.g. muscle, blood, nerve cells, immune system The molecules of life • • • • • Nucleic acids (DNA, RNA) Proteins Carbohydrates Lipids Lipoproteins, glycoproteins, vitamins…. Genomics The Genome Transcriptome Transcription DNA RNA DNA + DNA DNA Replication Cell division Translation Protein synthesis Protein The Proteome Proteomics PROTEINS • Chains of amino acids • Structural elements – – cell walls, membranes • Transport • Catalysts - enzymes • Communication - within cells, between cells • Cytokines • Signal transduction factors • Receptors • Vital for regulation of growth, cell division Schematic metabolic cycle Cellular components Nucleic acids, Carbohydrates, Protein, Fat Food Metabolic intermediates Carbohydrates, Fats, Glucose, Proteins NADP+ ADP + Pi ATP ATP NAD+ NAD+ NADH Wastes CO2, H2O, lactic acid NADH ADP + Pi NADPH Work Transport Assembly Movement Heat The Metabolome - Metabolomics Viruses • • • • • 0.02-0.3 micrometers diameter Genetic material: ss or ds DNA, RNA Protein coat Some enzymes Lipid envelope – enveloped/non enveloped viruses • Nomenclature semi-systematic – Hepatitis A Virus, HAV • Need host cell for replication The plasma membrane Lipid bilayer Glycoprotein Av. Width Glycolipid Sugar 7.5 nm Polar (75 Å) Non-polar (Lipid) Protein The Flu Virion Hemagglutinin Matrix protein Neuraminidase Lipid bilayer envelope • Envelope: lipid bilayer membrane + glycoproteins, typically acquired from host cell membranes • Capsid (protein coat): multiple copies of 1 or more proteins in an array Life-cycle of virus • Particle, virion • Infects host cell • Genetic material uses host’s replication apparatus to produce new viral components (capsid, core proteins, genetic material) • Components assemble into viral particles, exit host cell, sometimes lysing host cell • Each type of virus has its own specific host • Viruses that colonize bacteria are bacteriophage viruses (bacteriophages). www.virustaxonomyonline.com Viruses in the Environmment • Must be able to survive outside host cell • Non-enveloped viruses are more persistent than enveloped viruses – Lipid envelope more easily damaged, protein coat confers stability • Enteric viruses are almost all non-enveloped – Hepatitis A, poliovirus, noroviruses, rotaviruses – Transmitted by direct and indirect contact, fecally contaminated water, food, fomites and air. • Respiratory viruses, mostly enveloped • adenoviruses, coronaviruses, rhinoviruses, influenza viruses, • Transmitted by direct and indirect contact, air (aerosols) and fomites (some also by water and food). Unicellular organisms • • • • Bacteria - procaryotes Protozoa Algae - eucaryotes Fungi Procaryotic Cell (left) and Eucaryotic Cell (right) Procaryotes: Bacteria and Others Unicellular organisms Simple internal organization Multiply by binary fission Diameter ~0.5-1.0 micrometer Envelope: cytoplasmic membrane, cell wall & capsule (polysaccharide) Some have appendages: flagella: for locomotion pili: attachment to other cells for genetic transfer; virus receptor site Standard Linnean nomenclature: Genus species Diverse bacteria Gram positive Gram negative More bacterial types • • • • • • • Aerobes Anaerobes Facultative aerobes Rods (bacilli) Spherical (cocci) Comma-shaped (vibrios) Spiral (spirochetes) Bacteria in the Environment Some bacteria form spores: – highly resistant to physical and chemical agents and – very persistent in the environment Unicellular Eucaryotes: • More complex internal organization: – organelles: discrete nucleus, mitochondria • Wide range of sizes: 2 micrometers and larger Protozoa • Unicellular; non-photosynthetic; flexible cell membrane; no cell wall; some are parasites, have complex life-cycles • Wide range of sizes and shapes; 2 micrometers to 2 mm • Disease-causing: – Amoebae: Entamoeba histolytica – Flagellates: Giardia lamblia – Ciliates: Balantidum coli – Sporozoans: Plasmodium vivax – Coccidians: Cryptosporidium parvum – Microsporidia: Cyclosopora cayetanensis Cryptosporidium parvum oocysts: ~5 m diameter Wet mount by differential interference contrast microscopy Acid fast stain of fecal preparation Giardia lamblia cyst: ~10 x 8 micrometers More Protozoans: Fungi Fungi (yeasts and molds): •non-photosynthetic • immotile; •rigid cell wall Molds: •grow as branched, interlacing chains or filaments (hyphae) called mycelia Mitospores (conidia) of Penicillium, one of the asexual Ascomycota •Yeasts: • do not form mycelia •grow as single cells that bud •sexual reproduction possible Yeasts Algae • Photosynthetic • Rigid cell wall • Simple plants, protists, protozoa, plancton, derived from cyanobacteria ? • Wide range of sizes and shapes – 2 micrometers and larger • Some algae are harmful – Algal booms • Toxins – Anabaena, anatoxins Nostoc Helminths (Worms) • Multicellular animals • Some are human and/or animal parasites • Eggs pass via human and animal excreta to water, food, soil. • Several major groups: – Roundworms, Nematodes eg. Ascaris, Trichinella spiralis, hookworms – Flatworms Platyhelminthes: Cestodes (tapeworms): pork, beef tapeworms, and Trematodes (flukes) eg Schistosomes – Annelids (leeches) Necator (hookworm) eggs adult • Eggs hatch in soil • Infective stage: larvae • Penetrate skin, migrate to blood, lungs, trachea • or are ingested • Adults mature in intestine • Attach to intestinal walls – anemia – Necator americanus , Ancylostoma duodenale (hookworm) Trematodes • Schistosomes (blood flukes) • Liver fluke Cestodes • Head (scolex) attaches to tissue – beef tapeworm, Taenia saginata – pork tapeworm (T. solium) • Grows in intestine http://www.marvistavet.com/html/body_tapeworm.html Multicellular organisms • Plants • Animals – Invertebrates – Vertebrates