Lec 06 Fungi

What is the role of fungi and what do they not do?

don’t photosynthesize

they absorb nutrients from other organisms

What can fungi be?

decomposers

parasites

mutualists

What traits do fungi share with animals?

synthesize CHITIN

store energy as GLYCOGEN

some fungi have FLAGELLA similar to animal sperm

What are the 2 main fungal body forms?

yeasts

mycelia

What are yeasts?

single celled

reproduce by budding

What are mycelia?

Multicellular

composed of branching hyphae

What type of fungi can switch between yeast and mycelial forms?

Dimorphic fungi

What does coenocytic mean?

giant, continuous cells with many nuclei

Why do fungi grow certain ways?

maximizes surface area for nutrient absorption

The structure of fungi

mycelium

hyphae

septa

What is mycelium?

the body of a fungus

What is hyphae?

thread-like structures making up mycelium

What is septa?

divide hyphae into compartments,

Why does fungal diversity matter?

DECOMPOSE dead plants & animals— returning nutrients to the soil

•break down lignin & cellulose— most organisms can’t digest

How do fungi reproduce?

Primarily by spores

can be asexual or sexual

What are spores?

lightweight, wind-dispersed reproductive units

What are fungi loving spores resistant to?

extreme conditions such as cold

What do mating types prevent?

SELF FERTILIZATION

What are the names of the fungi fertilization stages?

Plasmogamy

karyogamy

What is plasmogamy?

fusion of cytoplasm between two compatible fungi

What is Karyogamy?

fusion of nuclei, which may occur days, months, or even years later!

What does delayed fertilization allow?

s GENETIC VARIATION without immediate nuclear fusion

What are the four reproductive stages and what occurs in them?

•PLASMOGAMY (fusion of cytoplasm) •HETEROKARYOTIC (two separate nuclei) •KARYOGAMY (fusion of nuclei) •

MEIOSIS (spore production)

What are the 4 major fungal reproductive structures?

ZYGOSPORANGIA + BASIDIA + ASCI

What is zygosporangia?

tough structures that protect spores

how do Zygosporangia form?

when 2 HYPHAE FUSE, creating a highly RESISTANT structure

How do basidiomycetes reproduce?

BASIDIA, CLUB-SHAPED STRUCTURES that produce 4 SPORES each

what do ASCOMYCETES form?

form reproductive structures called ASCI

What do ascus produce?

8 SPORES each, doubling the number found in BASIDIOMYCETES

What does mutualism mean?

both partners benefit

What are some common fungal mutualisms?

MYCORRHIZAE

ENDOPHYTES

LICHENS

What do •MYCORRHIZAL fungi do?

HELP PLANT ROOTS ABSORB NUTRIENTS

What do plants provide fungi with?

Sugars

What are the TWO TYPES OF MYCORRHIZAE?

•ECTOMYCORRHIZAL FUNGI — form a sheath around plant roots •

ARBUSCULAR MYCORRHIZAL FUNGI (AMF)— penetrate root cells for nutrient exchange

What are lichens?

a partnership between FUNGI & ALGAE OR CYANOBACTERIA

What do fungi provide?

STRUCTURE & WATER RETENTION

What do algae and cyanobacteria provide?

SUGARS through photosynthesis

Where do endophytes live?

INSIDE PLANT TISSUES, without harming the host

What do endophytes produce?

CHEMICALS that deter herbivores & prevent infections

What happends during the carbon cycle?

plants absorb CO2 & fungi release it back into the atmosphere

What do fungi do as decomposers?

•break down wood, leaves, & even dead animals

What is extracellular digestion?

fungi SECRETE ENZYMES to break down food outside their bodies

What is bioremidation?

some fungi degrade toxic pollutants, including oil spills & heavy metals

What was the first antibiotic discovered?

Penicillin from fungus

How does fungi work as medicine?

produce compounds that FIGHT BACTERIA, VIRUSES, & CANCER CELLS

Edible fungi?

mushrooms, trufes & morels

fermentation

Why do fungi matter?

play essential roles in ecosystems & human life •they are decomposers, mutualists & pathogens