Power Point

Lessons for

LOWER SIX

BIOLOGYBIOLOGY

SMJK Perempuan China Pulau PinangSMJK Perempuan China Pulau Pinang

FungiFungi Eukaryotic heterotrophsEukaryotic heterotrophs

Secrete digestive enzymes onto foodSecrete digestive enzymes onto food then absorb predigested foodthen absorb predigested food

Cell walls with Cell walls with chitinchitin

Fungi StructuresFungi Structures Fungi includeFungi include

unicellularunicellular yeastyeast filamentous, multicellularfilamentous, multicellular mold mold

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))

HyphaeHyphae In most fungiIn most fungi

perforated perforated septasepta (cross walls) divide hyphae (cross walls) divide hyphae into individual cellsinto individual cells

In some fungiIn some fungi zygomycetes and glomeromyceteszygomycetes and glomeromycetes hyphae are hyphae are coenocytic coenocytic ((form elongated, form elongated,

multinuclear cell)multinuclear cell)

Fungus Body PlanFungus Body Plan

ReproductionReproduction Most fungi reproduce sexually and Most fungi reproduce sexually and

asexually by asexually by sporesspores

SporesSpores produced on aerial hyphae produced on aerial hyphae land in suitable spot and germinateland in suitable spot and germinate

Germination of a SporeGermination of a Spore

Bud development

Asexual ReproductionAsexual Reproduction

PlasmogamyPlasmogamy Fungi of two different mating types Fungi of two different mating types

meet, hyphae fusemeet, hyphae fuse cytoplasm fusescytoplasm fuses nuclei remain separate nuclei remain separate

Fungi enter Fungi enter dikaryoticdikaryotic ( (n n + + nn) stage) stage each new cell has one nucleus of each typeeach new cell has one nucleus of each type

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

Genetic DivisionsGenetic Divisions MeiosisMeiosis

produces 4 different haploid (produces 4 different haploid (nn) nuclei) nuclei each nucleus becomes part of a spore each nucleus becomes part of a spore

Mitosis Mitosis forms new mycelia when spores germinate forms new mycelia when spores germinate

Asexual SporesAsexual Spores

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

When these spores germinateWhen these spores germinate they also develop into myceliathey also develop into mycelia

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 different mating 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 Life Cycles

Fungal Life Cycles

Flagellate CellsFlagellate Cells

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

Flagellate cells propel themselvesFlagellate cells propel themselves with single posterior flagellumwith single posterior flagellum

Platelike CristaePlatelike Cristae

Like animal cells, fungal cells have Like animal cells, fungal cells have platelike cristae in their mitochondriaplatelike cristae in their mitochondria

OpisthokontsOpisthokonts

Fungi are Fungi are opisthokontsopisthokonts along with animals and choanoflagellatesalong with animals and choanoflagellates based on chemical and structural based on chemical and structural

characteristics characteristics

Chyt

rids

Zygo

myc

etes

Glo

mer

omyc

e tes

Asco

myc

etes

Basi

dio m

ycet

es

Evolution of ascospores

Evolution of basidiospores

Evolution of dikaryotic stage

Loss of flagellum

Common flagellate ancestor

Fungal Evolution

ZygomycetesZygomycetes 11

Rhizopus Rhizopus (black bread mold)(black bread mold) forms forms haploidhaploid thallus thallus produces asexual spores and sexual sporesproduces asexual spores and sexual spores

Asexual spores germinateAsexual spores germinate form new thalliform new thalli

ZygomycetesZygomycetes 22

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

mating types form mating types form gametangiagametangia

PlasmogamyPlasmogamy occurs occurs as as gametangiagametangia fuse fuse

Zygomycetes 3Zygomycetes 3 KaryogamyKaryogamy occurs occurs

diploid zygotediploid zygote forms forms from which from which zygosporezygospore develops develops

Meiosis Meiosis produces recombinant haploid produces recombinant haploid zygosporeszygospores

Zygomycetes 4Zygomycetes 4

When When zygosporeszygospores germinate germinate each hypha develops a each hypha develops a sporangiumsporangium at its tip at its tip

Spores are releasedSpores are released develop into new hyphaedevelop into new hyphae

Zygomycete Life Cycle

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,

threadlike threadlike polar tubespolar tubes

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

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))

ConidiaConidia

AscocarpAscocarp

AsciAsci

AscomycetesAscomycetes 22 Haploid mycelia of opposite mating Haploid mycelia of opposite mating

types produce septate hyphaetypes produce septate hyphae

Plasmogamy occurs, nuclei exchanged Plasmogamy occurs, nuclei exchanged

Dikaryotic Dikaryotic n +n + n n stage occursstage occurs hyphae form, produce asci and ascocarphyphae form, produce asci and ascocarp

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 into produce 8 haploid nuclei that develop into

ascosporesascospores

When ascospores germinateWhen ascospores germinate can form new myceliacan form new mycelia

AscomycetesAscomycetes 44 Ascomycetes includeAscomycetes include

yeastsyeasts cup fungi cup fungi morels morels truffles truffles pink, brown, and blue-green molds pink, brown, and blue-green molds

Some ascomycetes form mycorrhizaeSome ascomycetes form mycorrhizae others form lichensothers form lichens

ConidiaIn asexual reproduction, hyphae produce haploid conidia that can develop into new mycelia.

Germinating conidium

ASEXUAL REPRODUCTION

(by conidia)ConidiophoreHaploid

(n)9When released,

ascospores germinate and form new haploid mycelia.

(+) mating type

Haploid mycelia of opposite mating types both produce coenocytic sexual hyphae.

1

() mating type

2Plasmogamy occurs as hyphae of the two mating types fuse and nuclei are exchanged.

8Each nucleus becomes incorporated into an ascospore.

Nuclei migratePlasmogamy

SEXUAL REPRODUCTION

Dikaryotic hyphae form and produce asci.

3HAPLOID ( n )

STAGE

Mature ascus has eight haploid ascospores

7Mitosis produces eight haploid nuclei.

DIKARYOTIC STAGE (n + n)

Second meiotic division

DIPLOID (2n)

STAGE

First meiotic division

Nuclei fuse

Developing ascus with n + n nuclei

Hyphae form an ascocarp.4

Zygote

Meiosis 6Meiosis occurs, forming four haploid nuclei.

Karyogamy

Ascocarp

5Karyogamy occurs in each ascus. Two haploid nuclei fuse, forming a diploid zygote nucleus.

Mycelium

10

Ascomycete Life Cycle

BasidiomycetesBasidiomycetes 11 Produce sexual spores (Produce sexual spores (basidiosporesbasidiospores))

on outside of on outside of basidium basidium

Basidia developBasidia develop on surface of on surface of gillsgills in mushrooms in mushrooms a type a type ofof basidiocarp basidiocarp (fruiting body) (fruiting body)

Hyphae in this phylum have septa Hyphae in this phylum have septa

Basidiomycete Fruiting BodiesBasidiomycete Fruiting Bodies

BasidiomycetesBasidiomycetes 22 Plasmogamy occursPlasmogamy occurs

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

Dikaryotic secondary mycelium forms Dikaryotic secondary mycelium forms

Basidiocarp developsBasidiocarp develops basidia form basidia form

BasidiomycetesBasidiomycetes 33 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

Basidium with BasidiosporesBasidium with Basidiospores

BasidiomycetesBasidiomycetes 44 Basidiomycetes includeBasidiomycetes include

mushroomsmushrooms puffballs puffballs bracket fungi bracket fungi rustsrusts smutssmuts

DecomposersDecomposers

Most fungi are Most 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

Mycorrhizae 1Mycorrhizae 1 Mutualistic relationships between fungi Mutualistic relationships between fungi

and roots of plantsand roots of plants

Fungus supplies water and nutrient Fungus supplies water and nutrient minerals to plantminerals to plant

Plant secretes organic compounds Plant secretes organic compounds needed by fungusneeded by fungus

Mycorrhizae 2Mycorrhizae 2 Glomeromycetes form endomycorrhizal Glomeromycetes form endomycorrhizal

associations with rootsassociations with roots

Ascomycetes and basidiomycetes form Ascomycetes and basidiomycetes form ectomycorrhizaeectomycorrhizae with tree roots with tree roots do not penetrate root cellsdo not penetrate root cells

LichenLichen Symbiotic combination of fungus and Symbiotic combination of fungus and

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

Photoautotroph provides fungus with Photoautotroph provides fungus with organic compounds, shelter, water, organic compounds, shelter, water, minerals minerals

LichensLichens

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 industrial to make citric acid and other industrial

chemicalschemicals

Edible AscomycetesEdible Ascomycetes

ResearchResearch Fungi are model organisms for Fungi are model organisms for

molecular biology and geneticsmolecular biology and genetics yeast yeast Saccharomyces cerevisiaeSaccharomyces cerevisiae other fungi other 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 Fungi are opportunistic pathogens in Fungi are opportunistic pathogens in

humans humans ringworm ringworm athletes foot athletes foot candidiasiscandidiasis histoplasmosishistoplasmosis

ToxinsToxins Some fungi produce Some fungi produce mycotoxinsmycotoxins

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

Fungal Plant DiseasesFungal Plant Diseases Fungal hyphae infect plants through Fungal hyphae infect plants through

stomata stomata hyphal branches (hyphal branches (haustoriahaustoria) ) penetrate plant cellspenetrate plant cells obtain nourishment from cytoplasm obtain nourishment from cytoplasm

IncludeInclude wheat rustwheat rust Dutch elm diseaseDutch elm disease chestnut blightchestnut blight

Fungal Infection of PlantsFungal Infection of Plants

Fungal Plant DiseasesFungal Plant Diseases

KEY CONCEPTSKEY CONCEPTS

Fungi are of major ecological, Fungi are of major ecological, economic, biological, and medical economic, biological, and medical importanceimportance

BIOLOGYFungiFungi StructuresHyphaeFungus Body PlanReproductionGermination of a Spore Slide 9PlasmogamyKaryogamyGenetic DivisionsAsexual SporesSlide 14Flagellate CellsPlatelike CristaeOpisthokontsSlide 18Zygomycetes 1Zygomycetes 2Zygomycetes 3Zygomycetes 4Slide 23MicrosporidiaSlide 25Ascomycetes 1Slide 27Ascomycetes 2Ascomycetes 3Ascomycetes 4Slide 31Basidiomycetes 1Basidiomycete Fruiting BodiesBasidiomycetes 2Basidiomycetes 3Basidium with BasidiosporesBasidiomycetes 4DecomposersMycorrhizae 1Mycorrhizae 2LichenLichensUseful FungiEdible AscomycetesResearchPathogensToxinsFungal Plant DiseasesFungal Infection of PlantsSlide 50KEY CONCEPTS