Microorganisms. Microorganisms. Chapter 17 ( , ) Chapter 31 ( ) Chapter 28 ( ) Bacteria Cyanobacteria Fungi Protists

Biology 1030 Winter 2009 Microorganisms Chapter 17 (556-560, 564-565) Chapter 31 (608-623) Chapter 28 (549-569) Scott circa 2009 Microorganisms • ...
Author: Charla Scott
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Biology 1030

Winter 2009

Microorganisms

Chapter 17 (556-560, 564-565) Chapter 31 (608-623) Chapter 28 (549-569) Scott circa 2009

Microorganisms • • • •

Bacteria Cyanobacteria Fungi Protists

Scott circa 2009

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Biology 1030

Winter 2009

Bacteria Are Wee 1 mm = 1000000

• Largest prokaryote is Epulopiscium fishelsoni – 600 μm !!! (= 0.6 mm)

100000

Size (nm)

• Average bacteria range from 1-5 μm

10000

• Smallest bacteria are the Mycoplasma

1 μm = 1000

– 120-250 nm 100 Scott circa 2009

Bacterial Cell Shapes • Coccus – Staphylococcus aureus

• Bacillus – Escherichia coli

• Coccobacillus – Brucella abortus

• Spiral – Helicobacter pylori

• Pleomorphic (many forms) – Mycobacteria

– Lack a rigid cell wall Scott circa 2009

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Biology 1030

Winter 2009

Bacterial Arrangements • Pairs – Neisseria gonorrhoeae

• Clusters – Staphylococcus aureus

• Chains – Streptococcus pneumoniaea

• Random

Scott circa 2009

Bacterial Structures Cell wall

• Cell Membrane • Cell Wall

Nucleoid

– Outer membrane

• Internal Structures – Nucleoid – Ribosomes

Capsule Sex pilus Fimbriae

• External Structures – Capsule – Pili – Flagella

• No organelles

Flagella

Scott circa 2009

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Biology 1030

Winter 2009

Cell Division in Bacteria • Binary fission – Continuous DNA synthesis – Continuous growth

Scott circa 2009

Cyanobacteria • Photosynthetic prokaryotes • Internal membrane structures • Anabaena • Heterocysts – Nitrogen fixation

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Biology 1030

Winter 2009

Nucleariids • Predecessor to all fungi • An opisthokont protist

Scott circa 2009

The Fungi • Not just mushrooms! • Hyphae – Tubular – Branched

• Mycelium – Aggregation

• Animal-like – Cell walls – Glycogen – Fats Scott circa 2009

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Biology 1030

Winter 2009

Biology of Fungi • Absorptive heterotrophs – Saprophytic

• Parasitic • Predatory – Arthrobotrys

Scott circa 2009

Fungal Life Cycle • Haplontic life cycle

PLASMOGAMY (fusion of cytoplasm)

KARYOGAMY ((fusion of nuclei))

Spore producing Spore-producing structures Spores

Heterokaryotic stage

ASEXUAL Mycelium REPRODUCTION

SEXUAL REPRODUCTION

Zygote

MEIOSIS GERMINATION

– – – –

Diploid zygote Haploid spores Haploid mycelium Plasmogamy • Heterokaryotic

– Karyogamy

GERMINATION

Spores

But … Some are diplontic Some are haplodiplontic

Scott circa 2009

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Biology 1030

Winter 2009

Fungal Spores • Common reproductive cell • Produced by: – Meiosis – sexual – Mitosis – asexual

Mycelia

• Divide by mitosis

Zygosporangium KARYOGAMY

Sporangia Spores Sporangium

Diploid nuclei

MEIOSIS

Mycelium Scott circa 2009

Fungal Gametes • Mitosis • Heterokaryotic mycelium

• Isogametes – + versus –

Mating type (+) PLASMOGAMY

Gametangia with haploid nuclei Mating type (–)

Young zygosporangium (heterokaryotic)

Zygosporangium Scott circa 2009

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Biology 1030

Winter 2009

Fungal Phyla • • • • •

Chytridiomycota Zygomycetes Glomeromycetes Ascomycetes Basidiomycetes

Scott circa 2009

Phylum Chytridiomycota • Ancestral fungi • Most are aquatic • Flagella – Gametes – Zoospores

• No mycelia y – Rhizoids

Scott circa 2009

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Biology 1030

Winter 2009

Phylum Zygomycetes • Aseptate hyphae – Coenocytic

• Asexual reproduction – Spores released from sporangia

• Sexual reproduction – – and + strains combine – Resilient zygosporangium – Karyogamy & meiosis

• Black bread mold (Lab 6) Scott circa 2009

Phylum Glomeromycetes • Very small group • Very significant group • Arbuscular mycorrhizae – 90-95% of plants

Scott circa 2009

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Biology 1030

Winter 2009

Phylum Ascomycetes • Septate hyphae • The sac fungi – Fruiting bodies Ascocarp – Sporangia (asci) • Meiosis • Mitosis • 8 ascospores

• Asexual spores – Conidia

Scott circa 2009

Phylum Basidiomycetes • Septate hyphae • The club fungi – Fruiting bodies Basidiocarp – Sporangia (basidia) • Meiosis • 4 basidiospores

• Long Long-lived lived dikaryotic stage

Scott circa 2009

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Biology 1030

Winter 2009

Decomposition • Saprophytic – Non-living food source

• Leaf litter – Locked in nutrients – Insoluble

Scott circa 2009

Extracellular Digestion • Hydrolytic enzymes • Absorptive heterotrophs

Scott circa 2009

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Biology 1030

Winter 2009

Parasitic Fungi • Heterotroph – Living organisms (host)

• Dutch elm disease – Mycelium infects xylem – Scarring

• Athletes foot

Scott circa 2009

Practical Mycology • Antibiotics –

3R*,4S*,5S*,6R*,7R*, 9R*,11R*, 12R*,13S*,14R*)-4-[(2,6-Dideoxy-3-C-methyl-3-O-methylα-L-ribo-hexopyranosyl)-oxy]-14-ethyl-7,12,13-trihydroxy-3, 5, 7, 9,11,13-hexamethyl-6[[3 4 6 trideoxy 3 (dimethylamino) β D xylo hexopyranosyl]oxy]oxacyclotetradecane [[3,4,6-trideoxy-3-(dimethylamino)-β-D-xylo-hexopyranosyl]oxy]oxacyclotetradecane2,10-dione

• Food

Scott circa 2009

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Biology 1030

Winter 2009

Autotrophic Protists • Photosynthetic – Algae

• All have chloroplasts – Source?

Scott circa 2009

Euglenoids • Plant-like

• Animal-like

– Chloroplasts – Photosynthesis

– No cell wall – Ingest nutrients Mixotrophs Long flagellum

Eyespot Short flagellum Contractile vacuole Chloroplast Plasma membrane

Pellicle

Scott circa 2009

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Biology 1030

Winter 2009

Evolution of Eukaryotes • Prokaryotic ancestor • Plasma membrane invaginates – Remember Anabaena

• Internal membranes – Endomembrane theory

Scott circa 2009

Endosymbiotic Theory • Serial endosymbiosis • Two possible mechanisms 1. Ingest but don’t kill 2. Infect but don’t kill

• First event y – Heterotrophic prokaryote – Mitochondrion

Scott circa 2009

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Biology 1030

Winter 2009

Endosymbiotic Theory • Second event – Autotrophic prokaryote – Chloroplast

Scott circa 2009

Endosymbiotic Theory • Third event – Autotrophic eukaryote – Chloroplast

• Evidence? Scott circa 2009

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Biology 1030

Winter 2009

The Algae • Grouped by ‘colour’ • Pigments in chloroplast – Chlorophyll a – Accessory pigments • Fucoxanthin

Brown Algae

Phycoerythrin

Red Algae

Chlorophyll b

Green Algae

Scott circa 2009

Algal Structure • Overall structure – Similarities to the land plants

• Blades – No true leaves

• Stipe – No true stems

• Holdfast – No true roots

Scott circa 2009

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Biology 1030

Winter 2009

Algal Structure • Predecessor of land plants

• Land plant

– Many similarities – Structure and function

• Cosmarium

Cell Wall Plasma Membrane Nucleus Plant Vacuole Chloroplast Pyrenoid

Scott circa 2009

Algal Life Cycles • Haplontic or Alternation of generations – No heterokaryotic stage

• Chlamydomonas

Gametes (n)





+ + Zoospore

FERTILIZATION

Mature cell (n)

Zygote (2n)

MEIOSIS

Scott circa 2009

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Biology 1030

Winter 2009

Lichens • Symbioses • Mycobiont – Ascomycetes

• Photobiont – Alga, cyanobacteria

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