Biology Test 2 Review

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BIOL 1113
Mary- Susan Potts- Santone

Biology Test #2 PROKARYOTES (Bacteria and Archaea): BACTERIA ● Structure: ○ Cell envelope (gram +/-) ○ Shapes: ■ cocci: round ■ baccili: rod ■ spirilli: spiral ○ Cytoplasm (no membrane bound organelles) ○ Appendages: ■ sex pilli: tube like structures: swapping plasmids (+ genes from surroundings) ● incorporate foreign DNA ■ fimbriae: hair like bristles- adhesion to surfaces ■ flagellum: rotating filament allowing locomotion ● 3 strands of flagellum wound in helix, inserted into hook/basal body ● Reproduction (no mitosis or meiosis): ○ Asexual: ■ binary fission: cloning of cell into daughter ones (quick way of division) ■ budding: cell grows in size and splits (not genetically identical) ○ Sexual: ■ Methods of recombination: ● conjugation: sex pilus forms between 2 cell: gen. mat. exchanged ● transformation: bacteria picks up free pieces of DNA, get incorporated in genome ● transduction: bacteriophages (=vectors) carry bits of bact. DNA between cells ● plasmids: small circular strand of DNA ● Endospores: (response to unfavorable conditions)- dormant stage ○ resistant to heat, radiation, disinfectants, desiccation ○ can live 100 years in state, then re-vitalize ○ frequent cause of contamination, issue in hospitals ○ ex: tetanus, anthrax, botulism, botox ● Oxygen requirements: ○ Obligate aerobes: only capable of growth in presence of O2 ○ Obligate anaerobes: unable to grow in presence of O2 ○ Facultative anaerobes: able to grow with or without O2 present ● Autotrophic Types: ○ Phototrophs: photosynthetic (energy from sun)- some do not produce O2 ■ some use solar energy to reduce CO2 into organic compounds ○ Chemoautotrophs: chemosynthetic (energy from chemicals) ■ don’t require O2, oxidize inorganic compounds, reduce CO2 to organic compounds, role in cycling of nitrogen and sulphur through ecosystem (Rhizobium = nitrogen fixation) ● Heterotrophs: ○ essential components of healthy ecosystem (can be free living or symbiotic) ○ chemoheterotrophs: take in organic nutrients ○ saprotrophs: (detritivores) decompose most large inorganic molecules ● Symbiosis: long term interaction between two or more organisms ○ mutualism: all involved organisms benefit ○ parasitism: host organisms suffers, auxiliary organism benefits ● common bacterial diseases - antibiotics ARCHAEA ● Methanogens: found in anaerobic marshes (mud flats) ○ methane = biogas --> climate change ● Halophiles: like extremely salty conditions- 12-15% (ocean= 3%) ○ require high salt concentration to grow ○ have chloride pumps in membrane ■ pump water into cell to maintain equal pressure, rather than having all the water enter the salty environment ● Thermoacidophiles: (pH 1-2) (80+ deg C) ○ high heat and acidic environment ○ plasma membranes contain specialized lipids with high heat tolerance PROTISTS ○ Domain Eukarya ○ Paraphyletic Group - very diverse - Life Cycles (Reproduction) i. Asexual - common ii. Sexual - occurs in deteriorating conditions - Ecological Importance ■ Photoautotrophic forms - produce oxygen, major component in plankton, serve as food to other protists ■ symbionts - parasitic to mutualistic ○ in tissues of corals - (Zooxanthellae) - Modes of Nutrition 1. Photoautotrophs - ex.) diatoms, euglena, green/red/brown algae, dinoflagellates 2. Heterotrophs - ex.) zooflagellates, amoeboids, ciliates 3. Saprotrophs - ex.) water mold - Evolution & Classification i. Plant-like ii. Fungi-like iii.Animal-like - Eukaryotic Supergroups (6 in total) ● Opisthokonts ○ Group Includes: Choanoflagellates,Animals, Plants ● Archaeplastids: (origin of land plants) ○ Group Includes: Green/RedAlgae, Land Plants -colonial, filamentous a. Green algae - unicellular and multicellular -variety of environments (ocean, freshwater, tree bark) -symbiotic w/ plants and animals -contain cellulose and chlorophyl a and b -store excess food as starch a. Red algae - multicellular -live in warmer marine water -most branched/feathered/flat - produce agar (used in capsules, food preparation) and carrogeen (emulsifying agent, chocolate, low fat foods) ● Chromalveolates: 1. -Brown algae - (approx 1500 species): seaweeds, kelp, rockweed, holdfast, -contain: stipe, blade, air bladder -colder ocean water along rocky coasts -no unicellular or colonial forms -produce oxygen -contain chlorophyll a and c -fucoxanthin is what gives brown appearance 1. Diatoms -(approx 100000 species) most numerous unicellular organism in ocean -example: phytoplankton -cell wall w/ 2 valves (larger valve acts lid) -contain silica -Commercial use: Diatomaceous Earth -filtering, polishing/abrasiveness, sound proofing ● Alveolates: 1. Dinoflagellates - (RED TIDE) a. symbiotic relationship with corals - Zooxanthellae i. Coral provides waste to fertilize, and Dinoflagellates provide coral w/ organic nutrients b. 2 flagella 2. Ciliates - Pellicle: outer boundary - Trichocysts: tiny hair-like structures that shoot out of the membrane, important in defense and feeding, inject toxins into prey -Two nuclei of differing types i. Micronucleus – Heredity ii. Macronucleus – Metabolism 3. Apicomplexans: - Nonmotile obligate parasites - Apical complex of organelles on merozoites/sporozoites i. apical complex: allows organism to penetrate body of host - Most serious parasitic disease of human is Malaria i. Toxoplasmosis: Causes birth defects and mental retardation when pregnant mom exposed ● Life Cycle of Plasmodium vivax: ○ Mosquito bites infected individual and picks up gametophyte stage ○ Sporozoites form and reside in salivary gland ○ Mosquito injects sporozoite stage into human ○ Sporozoites travel throughout immune system and stay in liver ○ Undergo tremendous asexual reproduction ○ Sporozoites (now merozoites) rupture liver cells and enter bloodstream ○ Merozoites are then taken into red blood cells ○ Merozoites reproduce in red blood cells causing them to rupture, then enter bloodstream ○ Infected blood cells become lodged (spleen can’t get rid of them) and merozoites continue to thrive ○ Some merozoites become gametocytes, which enter bloodstream and become gametes if taken up by mosquito Excavates: Euglenids: -Small freshwater unicellular organisms -Have two flagella and an eyespot -Projects out of an anterior, vase-shaped invagination -Called a tinsel flagellum because of hair-like projections -Cell bounded by flexible pellicle i. Chloroplasts: -Surrounded by three rather than two membranes -With a pyrenoid which produces an unusual type of carbohydrate called paramylon Zooflagellates: o Colorless heterotrophs – no/unusual mitochondria o Most symbiotic and many parasitic o Well known for causing various diseases in humans i. Trypanosoma - Kinetoplastid - African sleeping sickness ii. Giardia lamblia - Diplomonad - Most common flagellate in human digestive tract -Causes severe diarrhea Amoebozoans: o Pseudopods - caused by cytoplasmic streaming o move and ingest their food with pseudopods -Rhizarians Foraminiferans and Radiolarians Both have a skeleton (test) of either calcite (CaCO3) or silica -Slime Molds: o Key in decomposition (decomposers) o Plant diseases - Plasmodial Slime Molds: - Body in the form of a plasmodium - Diploid, multinucleated, cytoplasmic mass - Eventually produces sporangium which in turn produces spores -Cellular Slime Mold: - Body in the form of individual amoeboid cells - Later aggregate into pseudoplasmodium which then forms sporangium & spores - Water Molds: - Parasitize fish, insects, plants - Cell walls of cellulose · Opisthokonts -Choanoflagellates: -600 spp.; tiny (< 10µm) -Marine and freshwater -Solitary or colonial (colonial= attached to common stalk) - Attached or free-swimming -single flagellum surrounded by collar of microvilli -like a glass vase, with flagellum sticking out · Life Cycles: § Haploid (single set of unpaired chromosomes) life cycle: · Volvox, Dinoflagellates, Sporozoans, Trypanosomes · Zygote is 2n stage · Meiosis produces spores § Alternation of generations: · Green plants,Algae, Foraminiferans · Sporophyte is 2n generation · Meiosis produces spores · Gametophyte is n generation § Diploid (2 complete sets of chromosomes) life cycle: · Green algae, diatoms, ciliates, animals · Individual is always 2n · Meiosis produces gametes FUNGI -multicellular eukaryotes: 1.heterotrophic (saprotrophic decomposers -> detritivores) 2. release digestive enzymes and absorb the nutrients known as extracellular digestion 3. can be parasitic [ex): ringworm] 4. several mutualistic -Structure: 1. body (thallus) of most fungi are multicellular mycelium (vast network of thread-like hyphae) 2. hyphae (microscopic branched filaments)- grow from tip of thallus ○ septate fungi - hyphae w/ cross walls ○ nonseptate fungi - multinucleated, no cell walls in between 3. cell walls made of chitin 4. excess food stored as glycogen (similar to animals) 5. May have evolved from RedAlgae- both nonflagellated -REPRODUCTION: 1.sexual (mostly) and asexual (both nonmotile) - sexual 1. Haploid Hyphae (spore) 2. Dikaryotic Stage (fruiting body) 3. Zygote (Diploid stage) 4. Spore (from m
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