Microbiology Review Taxonomy Microbiology is the study of
Microbiology Review
Taxonomy • Microbiology - is the study of micro-organisms • Microorganism - any living that is too small to be seen with the naked eye. – found in the air, water, on plants or animals, and on people – some can make you sick, but most are harmful, and a few are beneficial. • Prokayotic - a type of cell that does not have its chromosomes surrounded by a nuclear envelope • Eukaryotic - a type of cell that has a true nucleus, surrounded by a nuclear envelope • Heterotroph - an organism that obtains energy by eating other organisms • Autotroph - an organism that obtains energy directly from light
Taxonomy • Scientists classify microorganisms into 5 different groups: – Viruses (not considered “living”) – Kingdom Eubacteria – Kingdom Archaebacteria – Kingdom Protista – Kingdom Fungi
Viruses • Viruses are very small, lifeless particles that carry out no metabolic functions (don’t breathe, no cellular respiration) and cannot reproduce without assistance. • In order to be able to reproduce the virus must invade a living cell. • Viruses are more simple in structure than living organisms – Instead of a cell membrane like living cells, viruses have a protein coat called a capsid – Inside the capsid is the nucleic acid (DNA or RNA) • A unique type of virus is a bacteriophage, which only infect bacterial cells.
Bacteria 1. Kingdom Eubacteria – prokaryotic (simple organisms lacking nuclei – composed of 1 cell (single-celled organism) that does not contain a cell nucleus – can be either autotrophs or heterotrophs – reproduce by asexual reproduction – live nearly everywhere – can cause disease – e. g. Bacteria and Blue-green algae
Bacteria 2. Kingdom Archeabacteria – Prokaryotic – Heterotrophs or autotrophs – Live nearly anywhere including salt lakes, hot springs, animal guts – Do not cause disease – Incude methanogens, thermophiles, halophiles
Bacteria Shape A) Cocci spherical --B) bacilli rod-shaped -------C) Spirilla spiral
Bacteria Configuration
Fighting Disease • Review the 3 levels of defense – External – Lymphatic System – Antibody Formation • Review types of immunity – Passive – Active
Kingdom Protista • Protozoa - Greek name meaning “first animal” • Eukaryotic - membrane bound organelles and a true nucleus • Most unicellular • Some autotrophic, some heterotrophic, some can switch between both types depending upon environmental conditions
3 Main Groups Protists 1. Animal Like Protists – – Eyespot – Cyst – Contractile Vacuole Rhizopods • move by pseudopodia (cytoplasmic streaming) • engulf food with pseudopodia • some have mineral skeletons (tests) Ciliates • move by beating cilia • food is swept into cell’s gullet by cilia • the most complex protozoans • require two or more nuclei Protozoans • unicellular • most are motile - living in aquatic environments • heterotrophic – food broken down in food vacuoles • reproduce by binary or multiple fission or conjugation • adaptations to survive in a variety of environments – – – Flagellates • move by beating flagella • most live within other organisms – Sporozoans • do not move physically • spores form for reproduction • spores move from host to host (parasitic)
2. Plant Like Protists • mostly autotrophic • live in soil, on the bark of trees, in fresh water, and in salt water • produce most of the atmospheric oxygen • form the base of aquatic food chains • reproduce asexually and sexually • unicellular, multicellular, or live in colonies Examples: – Euglenoids – Dinoflagellates – Algae – Diatoms (Bacillariophyta) – Golden Algae (Chrysophyta) – Green Algae (Chlorophyta) – Brown Algae (Phaephyta) – Red Algae (Rhodophyta)
3. Fungus-Like Protists • heterotrophs, they secrete digestive juices and then absorb the organism • have cell walls • use spores from fruiting body to reproduce • unlike fungus, they can move at some points in their life cycle – Oomycota (Water Moulds and Mildews) – Slime Moulds
Kingdom Fungi • Includes: i. iii. iv. v. Chytrids (water mould) Common moulds (bread mould) Yeast, morels & truffles Mushrooms Club-shaped (parasitic fungi) • The parts designed for nutrient absorption are often underground (called mycelium) – A mesh of microscopic filaments that branch out just below the surface – Each filament in the mesh is called a hypha Ø The cell walls of hyphae are often reinforced with chitin Ø Some hyphae contain cross-walls
Microorganisms in Ecosystems • There are three types of symbiotic relationships: – Parasitism (+/-) – Commensalism (+/0) – Mutualism (+/+)
Microorganisms in Biotechnology • Biotechnology is the use of living organisms for commercial applications • Recombinant DNA - used to insert DNA from other organisms in to bacteria (see human insulin diagram) • Also used to improve plant crops – – Resist pests Improve taste More nutrients Longer shelf-life • Viral Vectors -this method takes advantage of the virus’ attack plan – Recall that they ingest their DNA into the host cell to “hijack” it. • Only works with cells that are dividing • Will not work with brain and spinal cord cells
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