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Power

Point

Lessons for

LOWER SIX

BIOLOGYBIOLOGY

SMJK Perempuan China Pulau PinangSMJK Perempuan China Pulau Pinang

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FungiFungi

Eukaryotic heterotrophsEukaryotic heterotrophs

Secrete digestive enzymes onto foodSecrete digestive enzymes onto food

then absorb predigested foodthen absorb predigested food

Cell walls withCell walls with chitinchitin

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Fungi StructuresFungi Structures

Fungi includeFungi include

unicellularunicellularyeastyeast

filamentous, multicellularfilamentous, multicellularmoldmold

Most multicellular fungiMost multicellular fungi

have long, threadlike filamentshave long, threadlike filaments ((hyphaehyphae))

branch and form a tangled massbranch and form a tangled mass ((myceliummycelium))

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HyphaeHyphae

In most fungiIn most fungi

perforatedperforated septasepta (cross walls) divide hyphae(cross walls) divide hyphaeinto individual cellsinto individual cells

In some fungiIn some fungi

zygomycetes and glomeromyceteszygomycetes and glomeromycetes

hyphae arehyphae are

coenocyticcoenocytic

((form elongated,form elongated,

multinuclear cell)multinuclear cell)

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Fungus Body PlanFungus Body Plan

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ReproductionReproduction

Most fungi reproduce sexually andMost fungi reproduce sexually and

asexually byasexually by sporesspores

SporesSpores produced on aerial hyphaeproduced on aerial hyphae

land in suitable spot and germinateland in suitable spot and germinate

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Germination of a SporeGermination of a Spore

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Bud development

Asexual ReproductionAsexual Reproduction

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PlasmogamyPlasmogamy

Fungi of two different mating typesFungi of two different mating types

meet, hyphae fusemeet, hyphae fuse cytoplasm fusescytoplasm fuses

nuclei remain separatenuclei remain separate

Fungi enterFungi enterdikaryoticdikaryotic ((nn ++ nn) stage) stage

each new cell has one nucleus of each typeeach new cell has one nucleus of each type

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KaryogamyKaryogamy

Fusion of nucleiFusion of nuclei takes place in hyphal tiptakes place in hyphal tip

results in diploid (2results in diploid (2nn)) zygote nucleuszygote nucleus

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Genetic DivisionsGenetic Divisions

MeiosisMeiosis produces 4 different haploid (produces 4 different haploid (nn) nuclei) nuclei

each nucleus becomes part of a sporeeach nucleus becomes part of a spore

MitosisMitosis

forms new mycelia when spores germinateforms new mycelia when spores germinate

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Asexual SporesAsexual Spores

Can be produced by mitosisCan be produced by mitosis genetically similargenetically similar

When these spores germinateWhen these spores germinate

they also develop into myceliathey also develop into mycelia

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Large numbers of

haploid (n) spores are

produced by mitosis.

Spore germinates

and forms mycelium

by mitosis.Asexual

reproduction

1Spores germinate

and form mycelia

by mitosis.Mycelia

Mycelia of two differentmating types fuse at their

tips, and plasmogamy

(fusion of cytoplasm)

occurs.

2

6Spores are

released. Spores

Sexual

reproduction

Haploid stage

(n)

Dikaryotic stage

(n + n)5

Meiosis results in

four genetically

different haploid ( n )nuclei. Spores

develop around

nuclei.

Diploid

stage (2n) 3

Zygote nucleus(2n)

Dikaryotic (n + n)

mycelium develops.

Dikaryotic mycelium

4 Karyogamy (fusion of nuclei)

occurs, forming a diploid (2 n )zygote nucleus.

7 8

Meiosis Karyogamy

Plasmogamy

Fungal LifeFungal Life

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Flagellate CellsFlagellate Cells

Animals and fungi haveAnimals and fungi have flagellate cellsflagellate cells Example: chytrid gametes and sporesExample: chytrid gametes and spores

Flagellate cells propel themselvesFlagellate cells propel themselves

with single posterior flagellumwith single posterior flagellum

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Platelike CristaePlatelike Cristae

Like animal cells, fungal cells haveLike animal cells, fungal cells haveplatelike cristae in their mitochondriaplatelike cristae in their mitochondria

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OpisthokontsOpisthokonts

Fungi areFungi are opisthokontsopisthokonts along with animals and choanoflagellatesalong with animals and choanoflagellates

based on chemical and structuralbased on chemical and structural

characteristicscharacteristics

s s

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Ch

ytrid

s

Zygomyce

tes

Glo

mer omyce

tes

As

comyce

tes

Ba

sidio

myce

tes

Evolution of

ascospores

Evolution ofbasidiospores

Evolution of

dikaryotic stage

Loss of flagellum

Common

flagellate

ancestor

Fungal

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ZygomycetesZygomycetes 11

RhizopusRhizopus (black bread mold)(black bread mold) formsforms haploidhaploidthallusthallus

produces asexual spores and sexual sporesproduces asexual spores and sexual spores

Asexual spores germinateAsexual spores germinate

form new thalliform new thalli

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ZygomycetesZygomycetes 22

In sexual reproductionIn sexual reproduction hyphae of 2 different haploidhyphae of 2 different haploid

mating types formmating types form gametangiagametangia

PlasmogamyPlasmogamy occursoccurs

asas gametangiagametangia fusefuse

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Zygomycetes 3Zygomycetes 3

KaryogamyKaryogamy occursoccurs

diploid zygotediploid zygote formsforms from whichfrom which zygosporezygospore developsdevelops

MeiosisMeiosis

produces recombinant haploidproduces recombinant haploid zygosporeszygospores

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Zygomycetes 4Zygomycetes 4

WhenWhen zygosporeszygospores germinategerminate each hypha develops aeach hypha develops a sporangiumsporangium at its tipat its tip

Spores are releasedSpores are released

develop into new hyphaedevelop into new hyphae

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Zygomycete

Life Cycle

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MicrosporidiaMicrosporidia

MicrosporidiaMicrosporidia (now zygomycetes)(now zygomycetes) are opportunistic pathogensare opportunistic pathogens

penetrate and infect animal cells with long,penetrate and infect animal cells with long,

threadlikethreadlike polar tubespolar tubes

I f ti b

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Host cell

2. Spore ejects

its polar tube

and penetrates

host cell.

3. Infective

cytoplasm is

injected into

host cell.

Microsporidian cell

Polar tube

1. Spore of

microsporidium

has coiled

polar tube.

Infection by

Microsporidium

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AscomycetesAscomycetes 11

Produce asexual spores (Produce asexual spores (conidiaconidia))

Produce sexual spores (Produce sexual spores (ascosporesascospores) in asci) in asci

Asci line a fruiting body (Asci line a fruiting body (ascocarpascocarp))

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ConidiaConidia

AscocarpAscocarp

AsciAsci

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Haploid mycelia of opposite matingHaploid mycelia of opposite mating

types produce septate hyphaetypes produce septate hyphae

Plasmogamy occurs, nuclei exchangedPlasmogamy occurs, nuclei exchanged

DikaryoticDikaryotic n +n +nn stage occursstage occurs

hyphae form, produce asci and ascocarphyphae form, produce asci and ascocarp

A 3

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Ascomycetes 3Ascomycetes 3

Karyogamy occursKaryogamy occurs

followed by meiosisfollowed by meiosis

Recombinant nuclei divide by mitosisRecombinant nuclei divide by mitosis

produce 8 haploid nuclei that develop intoproduce 8 haploid nuclei that develop into

ascosporesascospores

When ascospores germinateWhen ascospores germinate

can form new myceliacan form new mycelia

A t 4

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Ascomycetes includeAscomycetes include

yeastsyeasts cup fungicup fungi

morelsmorels

trufflestruffles

pink, brown, and blue-green moldspink, brown, and blue-green molds

Some ascomycetes form mycorrhizaeSome ascomycetes form mycorrhizae

others form lichensothers form lichens

Conidia Germinating10

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In asexual reproduction,

hyphae produce haploid

conidia that can develop

into new mycelia.

Germinating

conidium

ASEXUAL

REPRODUCTION

(by conidia)Conidiophore

Haploid

(n)

9When released,

ascosporesgerminate and

form new

haploid mycelia.

(+) mating

type

Haploid mycelia of

opposite mating typesboth produce coenocytic

sexual hyphae.

1

() matingtype

2

Plasmogamy occurs ashyphae of the two matingtypes fuse and nuclei are

exchanged.

8Each nucleus

becomes

incorporatedinto an

ascospore.

Nuclei migrate

Plasmogamy

SEXUALREPRODUCTION

Dikaryotichyphae formand produceasci.

3HAPLOID ( n )STAGE

Mature ascus has

eight haploid

ascospores

7

Mitosisproduces eighthaploid nuclei.

DIKARYOTICSTAGE(n + n)

Second meioticdivision

DIPLOID

(2n)

STAGE

Firstmeioticdivision

Nucleifuse

Developingascus

withn + nnuclei

Hyphaeform anascocarp.4

Zygote

Meiosis6Meiosis occurs, forming

four haploid nuclei.Karyogamy

Ascocarp

5

Karyogamy occurs in each ascus.

Two haploid nuclei fuse, forming adiploid zygote nucleus.

Mycelium

10

Ascomycete

Life Cycle

B idi tB idi t 11

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BasidiomycetesBasidiomycetes 11

Produce sexual spores (Produce sexual spores (basidiosporesbasidiospores))

on outside ofon outside ofbasidiumbasidium

Basidia developBasidia develop

on surface ofon surface ofgillsgills in mushroomsin mushrooms

a typea type ofofbasidiocarpbasidiocarp (fruiting body)(fruiting body)

Hyphae in this phylum have septaHyphae in this phylum have septa

B idi t F iti B diB idi t F iti B di

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Basidiomycete Fruiting BodiesBasidiomycete Fruiting Bodies

B idi tB idi t 22

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Plasmogamy occursPlasmogamy occurs

fusion of 2 hyphae of different mating typesfusion of 2 hyphae of different mating types

Dikaryotic secondary mycelium formsDikaryotic secondary mycelium forms

Basidiocarp developsBasidiocarp develops

basidia formbasidia form

B idi tB idi t 33

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Karyogamy occursKaryogamy occurs

producing diploid zygote nucleusproducing diploid zygote nucleus

Meiosis produces 4 haploid nucleiMeiosis produces 4 haploid nuclei

become basidiosporesbecome basidiospores

When basidiospores germinateWhen basidiospores germinate

form haploid primary myceliaform haploid primary mycelia

B idi ith B idiB idi ith B idi

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Basidium with BasidiosporesBasidium with Basidiospores

B idi tB idi t 44

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Basidiomycetes includeBasidiomycetes include

mushroomsmushrooms puffballspuffballs

bracket fungibracket fungi

rustsrusts

smutssmuts

DD

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DecomposersDecomposers

Most fungi areMost fungi are decomposersdecomposers break down organic compoundsbreak down organic compounds

dead organisms, leaves, garbage, wastesdead organisms, leaves, garbage, wastes

into simpler nutrients that can be recycledinto simpler nutrients that can be recycled

M hi 1M hi 1

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Mycorrhizae 1Mycorrhizae 1

Mutualistic relationships between fungiMutualistic relationships between fungi

and roots of plantsand roots of plants

Fungus supplies water and nutrientFungus supplies water and nutrient

minerals to plantminerals to plant

Plant secretes organic compoundsPlant secretes organic compoundsneeded by fungusneeded by fungus

M hi 2M corrhi ae 2

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Mycorrhizae 2Mycorrhizae 2

Glomeromycetes form endomycorrhizalGlomeromycetes form endomycorrhizal

associations with rootsassociations with roots

Ascomycetes and basidiomycetes formAscomycetes and basidiomycetes form

ectomycorrhizaeectomycorrhizae with tree rootswith tree roots

do not penetrate root cellsdo not penetrate root cells

Li hLichen

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LichenLichen

Symbiotic combination of fungus andSymbiotic combination of fungus and

photoautotroph (alga / cyanobacterium)photoautotroph (alga / cyanobacterium)

Photoautotroph provides fungus withPhotoautotroph provides fungus with

organic compounds, shelter, water,organic compounds, shelter, water,

mineralsminerals

LichensLichens

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LichensLichens

Useful FungiUseful Fungi

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Useful FungiUseful Fungi

Fungi are usedFungi are used

as foods (mushrooms, morels, truffles)as foods (mushrooms, morels, truffles) in production of beer, wine, bread (yeasts)in production of beer, wine, bread (yeasts)

to produce cheeses and soy sauceto produce cheeses and soy sauce

to make citric acid and other industrialto make citric acid and other industrialchemicalschemicals

Edible AscomycetesEdible Ascomycetes

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Edible AscomycetesEdible Ascomycetes

ResearchResearch

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ResearchResearch

Fungi are model organisms forFungi are model organisms for

molecular biology and geneticsmolecular biology and genetics yeastyeast Saccharomyces cerevisiaeSaccharomyces cerevisiae

other fungiother fungi

Biological control of insectsBiological control of insects such as mosquitoes that transmit malariasuch as mosquitoes that transmit malaria

Medications Fungi are used to make medications

penicillin, other antibiotics

PathogensPathogens

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PathogensPathogens

Fungi are opportunistic pathogens inFungi are opportunistic pathogens in

humanshumans ringwormringworm

athletes footathletes foot

candidiasiscandidiasis histoplasmosishistoplasmosis

ToxinsToxins

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ToxinsToxins

Some fungi produceSome fungi produce mycotoxinsmycotoxins

such assuch as aflatoxinsaflatoxins cause liver damage and cancercause liver damage and cancer

Fungal Plant DiseasesFungal Plant Diseases

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Fungal hyphae infect plants throughFungal hyphae infect plants through

stomatastomata hyphal branches (hyphal branches (haustoriahaustoria)) penetrate plant cellspenetrate plant cells

obtain nourishment from cytoplasmobtain nourishment from cytoplasm

IncludeInclude

wheat rustwheat rust

Dutch elm diseaseDutch elm disease

chestnut blightchestnut blight

Fungal Infection of PlantsFungal Infection of Plants

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Fungal Infection of PlantsFungal Infection of Plants


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KEY CONCEPTSKEY CONCEPTS

Fungi are of major ecological,Fungi are of major ecological,

economic, biological, and medicaleconomic, biological, and medical

importanceimportance

fungi 2009

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