Topic 12 - Fungi Flashcards Preview

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Flashcards in Topic 12 - Fungi Deck (22):
1

Key features of Fungi?

Body is composed of thin filaments (hyphae)
Hyphae form an interwoven mat (mycelium)
Hyphae are formed of single, elongated cells or multiple cells connected by septa
Cells are bound by cell walls (composed of chitin)

2

What periodically sprouts above the mycelium?

reproductive structures

3

What kind of feeders are Fungi?

heterotrophic

4

List sources where Fungi obtain nutrients

-dead organisms
-parasitism on living organisms
-symbiotic relationships with food providers
-predation

5

How do Fungi digest food?

Digested extracellularly by secreting enzymes; nutrients are resorbed by hyphae

6

Explain fungal propagation

Propagation is via spores
-tiny propagules germinate to produce next generation=>are extremely light (carried in wind)=>often produced in lrg numbers

7

2 kinds of fungal repro?

Asexual
Sexual

8

Fungal cells and spores are..?

haploid

9

Explain asexual repro in fungi?

Occurs in stable environments
fruiting bodies grow above mycelium & release haploid spores (produced via mitosis)
results in rapid repro of genetically IDENTICAL individuals

10

Explain sexual repro in fungi?

Occurs when enviro conditions deteriorate
hyphae of 2 compatible mating types fuse
nuclei fuse=>form zygote
Zygote undergoes meiosis=>forming haploid sexual spores
Spores are released=>germinate
Resulting offspring are genetically DISTINCT from parent cells

11

Major fungal groups (taxa) are?

Chytrids
Zygomycetes
Glomeromycetes
Ascomycetes
Basidiomycetes

12

A bit about Chytrids?

Live in water (unique!)
Spores swim via flagella
Feed mainly on dead aquatic plants
Some are parasitic

13

A bit about Zygomycetes?

Typically live in soil
feed on decaying organic matter
Asex. repro is common, but sex. repro does occur
Example: bread mould

14

A bit about Glomeromycetes?

Grow in intimate association of plant roots (actually penetrate root cells)
This association is symbiotic (mycorrhiza)
Important in plant nutrition
Repro. mechanism is unkown

15

A bit about Basidiomycetes? *

Known as "club fungi" =>produce club shaped repro. structures
Reproduction is sexual
Incl. most of edible mushrooms

16

A bit about Ascomycetes? *

Known as "sac fungi" => spores contained in a sac
Repro. is sexual or asexual
Diversity of forms: wood decay fungi, moulds on fruit n veg (penicillium), yeasts (unicellular)

17

Basidiomycetes life cycle?
Ascomycetes life cycle see diagram in lectures (need to know)

Sexual repro when 2 hyphae fuse=>fused hyphae grow into mycelium containing a haploid nucleus from each parent=>Hyphae from mycelium form mushroom=>repro. cells called basidia form on mushy gills=>2 haploid nuclei in each basidium fuse to form a diploid nucleus=>dip. nucleus divides by meiosis=>gives rise to haploid basidiospores=>these are ejected & germinate

18

Major types of mutualistic interactions b/w fungi & other eukaryotic organisms?

Lichens- fungus provides support & protection, also provides food (photosynthate)

Mycorrhizae- intimate assoc. of fungus & plant root, fungus gets photosynthate from plant, plant gets more efficient water extraction from soil

Endophytes- grow w/in above ground plants, can be parasitic or produce beneficial chemicals that deter herbivores

19

Explain fungi's role as decomposer

Only fungi can digest both lignin & cellulose
Liberate nutrients tied up in dead organisms

20

Agricultural importance?

Plant pathogens (smuts, rusts)
Storage fungi (penicillium)
Landscape pests (kill plants)
Beneficial fungi (parasite/disease to arthropods)

21

Negative role of fungi in human health?

Diseases of skin (ringworm, athlete's foot)
Vaginal infections (yeast infection)
Disease of lungs

22

Positive role of fungi in human health?

Antibiotics (penicillin, cephalosporin, cyclosporin)
Food (soy sauce, cheese, mushy itself)
Beverage production (alcohol)
Bread production (yeasts)