EXAM 3 Flashcards
What role does pigment in fungi play?
Protective role against ultraviolet radiation
The rigid layers of fungal cell walls contain complex polysaccharides called?
Chitin and Glucan
Chitin provides…?
structural strength to cell walls of fungi
Fungal plasma membranes are stabilized by?
Ergosterol
What is Ergosterol?
Steroid molecule that replaces the cholesterol found in animal cell membranes
Chytrid
Type of fungi that live in aquatic environments and are the only fungi that are flagellated
What is the main fungus body called
Mycelium
Mycelium
Network of threat like hyphae (hypha singular) often unseen either underground or within the host
Septate hyphae
hyphae that is split into various cells
Coenocytic hypha
multinucleate organism with no cross section cell walls
What makes fungi absorptive heterotrophs
They hyphae feed by absorbing simple organic compounds
Saprobes
Fungi that feed on decaying / dead plant matter
Haustoria
Specialized hyphae that penetrates the cell walls of the host plant without killing the cell
Fungal Reproduction
Can be sexual and asexual spores
Spores are haploid and dispersed by air/water to new resources
Asexual Fungal Reproduction
Asexual spores are made through mitosis and grow genetically identical mycelia
Types of Asexual spores
Conidiospores and sporangiospores
Conidiospores
Where the hyphae is created and has no reproductive sac and are released directly
Sporangiospores
Contain special reproductive sac where spores are released from.
Asexual fungal reproduction produces…
genetically identical mycelium
budding
Bulge forms on side of the cell, nucleus divides through mitosis and detaches itself from the mother cell.
Fragmentation
bits of mycelium can grow into new individual mycelium.
Sexual reproduction happens in fungi when…
environmental conditions are unfavorable
Do fungi have genders?
No, they have mating types which are (+) and (-)
Homothallic
self fertile; when both mating types are present in the same mycelium
Heterothalic
Mycelia require two different but compatible mycelia to reproduce sexually
Steps to form a zygote (fungi)
- plasmogamy
- heterokaryotic stage
- karyogamy
plasmogamy
fusion of haploid (+) & (-) hyphae
heterokaryotic stage
hyphae with unfused haploid nuclei of both + and -
Karyogamy
fusion of haploid nuclei to form zygote
What are the characteristics of Chytridomycota?
Aquatic decomposers, flagellated, with motile zoospores, unicellular
What are the characteristics of Zygomycota?
zygosporangium (strong resistants), coenocytic hyphae, saprobes
What are the characteristics of ascomycota?
Ascopores (sexual spores) released in ascus
Conidiospores (asexual spores) released by conidiophores
What are the characteristics of Basidiomycetes?
Basidospores (sexual) found within basidium
Basidia (reproductive organ) contained within familiar mushroom (underside flappy bit of mushrooms)
What are the characteristics of Glomeromycetes?
arbuscular mycorrhizae
Fungi as decomposers are important because?
Break down dead tissue (including lignin)
Ectomycorrhizae
fungus remains outside root and is between cells.
What phylum of fungi form ectomycorrhizae
ascomycota, basiliomycota, zygomycota
Endomycorrrhizae / arbuscular mycorrhizae
fungi penetrate cell walls and form haustoria
What phylum of fungi form endomycorrhizae
Glomeromycetes
Lichens
Mutalistic relationship between an algae cell and fungal hypahe
Soredia
structure of lichen; algal + fungal partner
Ergot
infection in plants caused by mycotoxins
Ergotism
infection in animals and humans cause by mycotoxins in fungi
Adaptations plants developed from water to land
alteration of generations, apical meristem tissue, waxy cuticle, lignin in cell walls
Alteration of Generations
2n and n multicellular forms; gameophyte (n) and sporophyte (2n)
Apical Meristem tissue
Tissue that allows the root and shoot to grow towards ground resources (minerals and water) and towards sunlight respectfully.
Walled haploid spores
made with multicellular sporangium and is protected by sporopollenin (sporophye generation)
Multicellular gameangia (male)
gameophyte generation; sperm is protected within antheridium
Multicellular gameangia (female)
egg is protected within archegonium; this is where fertilization occurs.
Waxy Cuticle
Prevents desiccation (drying out) and allows for the exchange of CO2 and O2. Process is controlled through stomata
Secondary metabolites
chemicals that deter, repel, or poison competitors, herbivores and parasites
ex: caffeine, latex rubber
Mycorrhizae
mutalism with fungi; helps water and mineral absorption for plants and fungi get glucose from plant
Seedless, nonvascular plants
Bryophytes
Characteristics of seedless nonvascular plants
require water for reproduction and have rhizoids (not true roots)
Characteristics of Bryophytes
-Haploid gametophyte is dominant
-sporophyte dependent on gametophyte
-grows within archegonium of gametophyte
-sporangium makes haploid spores
3 phyla of bryophytes
Liverworts, hornworts, mosses
Structure of sporophyte
Foot, Seta, capsule
Capsule
Sporangium; produces spores via meiosis
Seta
stock that moves nutrients to sporangium (capsule)
Foot
in archagonium; absorbs nutrients from the female gametophyte
Seedless Vascular Plants Characteristics
Sporophytes are independent of gametophyte for nutrition
Diploid sporophyte dominates life cycle
Transport in Xylem and Phloem
True roots and true leaves
Xylem
cells specialized to move water and minerals
Phloem
cells specialized to move sugar, amino acids, and other organic products
What plants have microphylls?
Lycophytes ONLY
microphyll leaves
leaves with unbranched vascular tissue
megaphyll leaves
leaves with branched vascular tissue
What plants have megaphyll leaves?
all vascular plants except for lycophytes
Sporophylls
Leaves modified to bear sporangia; they tend to have sori on the underside of their leaves