BIOL110s05-33 - BIOL 110 Principles of Biology Spring 2005...

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Unformatted text preview: BIOL 110: Principles of Biology Spring 2005 Lecture 33, M 4/20/05 • ONLINE Quizzes link: [Quiz #6 up ASAP.] – (Cañada College I.D. [G#] for login and password) – Time-limited (so study well first!); ~ 30 minutes to complete – Can view twice, submit once only. • Last chance to do Quiz #5 TODAY!!! (11:45pm) • Midterm #3 Study Guides Available: USE THEM!!! – Exam 3 THIS FRIDAY!! Review in Lab today, 12:30pm! • Next: 18 (bits of 19), 25, 23, 29-31, 32….. REVIEW: • Ch. 14: Origin of Life, & Microbiology – The Prokaryotes: Bacteria & Archaea – Protists: Animal-like, plant-like, fungus-like • Simple but very diverse [single-celled] Eukaryotes [single- TODAY: • Ch. 14: Origin of Life, & Microbiology – Protists: Animal-like, plant-like, fungus-like • The Multicelled algae…. algae… – Fungi – spores, growth & reproduction • Symbioses (“living together”). (“ together” 1 E. Multicellular Algae • • • • All photosynthesize with chlorophyll Chloroplasts Cellulose cell walls Likely ancestors of land plants 1. Phaeophyta = brown 2. Rhodophyta = red 3. Chlorophyta = green bladder bladder blade 1. Brown Algae (Phaeophyta) • 1,500 species stipe • Most abundant in temperate seas • Contain chlorophylls a and c, and fucoxanthin holdfast Macrocystis • Range in size from tiny filaments to giant kelps 2 2. Red Algae (Rhodophyta) • • • • 4,100 species Most abundant in tropical seas Can grow at great depths (phycobilins) Complex life cycles may include very different forms Porphyra Life Cycle sporophyte (2n) zygote fertilization Diploid Stage Haploid Stage meiosis germinating spore (n) male gametes female gametes gametophyte (n) 10 cm 3 3. Green Algae (Chlorophyta) • 7,000 species • Resemble plants – Chlorophylls a and b – Starch grains in chloroplasts – Cell walls of cellulose, pectins Volvox Ulva spores F. Cellular Slime Mold • Amoeboid cells aggregate to form migrating mass, fruiting body • Used for studies of development culmination mitotic cell division mature fruiting body aggregation life cycle of Dictyostelium discoideum either or migrating slug stage 4 V. Fungal Characteristics • Heterotrophs • Most are saprobes saprobes – Get nutrients from nonliving organic matter • Some are parasites – Extract nutrients from a living host Fungal Groups • • Most fungi are multicelled Three groups are defined on the basis of their sexual spores: 1. Zygomycetes – Bread mold 2. Sac fungi (Ascomycetes) – Yeasts, blights, morels, truffles 3. Club fungi (Basidiomycetes) – Mushrooms, puffballs 5 The Mycelium • Most fungi produce a multicellular feeding structure called a mycelium mycelium • It consists of branching tubular cells called hyphae hyphae • Cell walls contain chitin chitin Mushrooms can cause permanent delusions. Just say No! Club Fungus Life Cycle nuclear fusion Diploid Stage Haploid Stage meiosis clubshaped structures with two nuclei (n + n) gills cap stalk spores (n) form spores released germination, mycelium forms “dikaryotic” (n + n) mycelium cytoplasmic fusion 6 Fungal Spores • Made up of one or a few cells • Can resist dehydration • Remain dormant until environmental conditions favor germination • Produced asexually or sexually Types of Sexual Spores** 1.Zygomycete hyphae fuse to produce a thickwalled zygospore 2.Sac fungi produce ascospores inside a parent cell called an ascus 3.Club fungi make basidiospores on the surface of a club-shaped cell (basidium) 7 III. Fungi as Mutualists • Symbiosis = Living together – Mutualism = both partners benefit – Commensalism = one benefits, other neutral (no benefit nor harm) – Parasitism = one benefits, other harmed • Lichens • Mycorrhizae A. Lichen: A Composite Organism • Fungus plus a photosynthetic partner – Fungal component usually is ascomycete – Partner is cyanobacteria or green algae • Fungus composes bulk of the structure – “Alice Algae and Freddie Fungi took a lichen to each other” lichen 8 Lichen Cross Section dispersal fragment photosynthetic species outer fungal cells • “Fungus-root”; Mutualism between a fungus and a plant root • Fungus gets sugars from plant • Plant gets minerals from fungus – Water, phosphates B. Mycorrhizae • Many plants do not grow well without mycorrhizae – Orchids; Evergreens/pines/furs 9 IV. Fungal Foes • Most fungi are vital decomposers and plant symbionts • A small proportion are plant pathogens • A tiny minority harm human health – (asco.) Valley fever – Candida (“yeast”) infections – Ringworm – Athlete's foot – Ascomycetes: Chestnut blight, Dutch elm disease Ascomycetes: – (basidio.) Toxic ‘Shrooms!! basidio.) Shrooms!! MT3 Review: 1. DNA structure & function: 1. AT, GC, antiparallel, helix, semi-conservative replication; 1. antiparallel, semi2. Griffiths and Hershey/Chase experiments. 2. Manipulating genes: 1. Restriction enzymes, molecular cloning, 2. PCR, Hybridization/probing, Gene Library 3. Evolution: Darwin’s observations, influences, and conclusions • Types of selection, Lamarck; Mutation = raw material Lamarck; 4. Early Life and Microbiology 1. Stanley Miller experiment • conditions of early life/biomolecules life/biomolecules 2. Prokaryotes – bacteria & archaea 3. Eukaryotic microbes 1. Protists: Flagellates, Ciliates, Amoeboid, Algae, etc. Protists: 2. Fungi: Zygomycota, Ascomycota, Basidiomycota Zygomycota, Ascomycota, 3. Symbioses ***: Lichens, Mycorrhizae 10 VII. Virus • • • Noncellular infectious agent Protein wrapped around a nucleic acid core Cannot reproduce itself; can only be reproduced using a host cell • Not truly alive outside a host cell Viral Body Plans • Genetic material is DNA or RNA • Coat is protein Helical virus Polyhedral virus Complex virus (bacteriophage) 11 ...
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