Lecture 13

Question 1

Kingdom Fungi

Answer 1

within Opisthokonta clade along with Animalia, colonized land around 475 MYA possibly as symbionts of plants

Question 2

5 main groups of fungi

Answer 2

1. Chytridiomycota
2. Zygomycota
3. Glomeromycota
4. Ascomycota
5. Basidiomycota

Question 3

6 fungi characteristics

Answer 3

1. chemoheterotrophs
2. external digestion
3. cell walls made of chitin
4. bodies composed of hyphae
5. large surface area:volume ratio (due to filamentous structure)
6. produce haploid spores asexually or sexually

Question 4

external digestion

Answer 4

secrete powerful enzymes outside body, break down large complex organic molecules (cellulose/lignin in plants and chitin/keratin in animals) into small, simple ones absorbed by body

Question 5

chitin

Answer 5

nitrogenous polysaccharide that evolved independently in some invertebrates, makes up cell wall in fungi

Question 6

hyphae

Answer 6

delicate chitin tubes surrounding cytoplasm that compose bodies of fungi

Question 7

mycelium

Answer 7

interwoven hyphal mat, acts as feeding network, can be very large

Question 8

2 types of hyphae

Answer 8

1. septate

2. coenocytic

Question 9

septate hyphae

Answer 9

have cross-walls (septa) dividing cells into separate
chambers, but holes in walls allow
cytoplasm and sometimes nuclei to travel through

Question 10

coenocytic hyphae

Answer 10

lack cross walls, continuous cytoplasm with hundreds

or thousands of nuclei

Question 11

hyphae growth

Answer 11

more area for enzyme secretion and food absorption, can grow quickly because proteins are sent to growing tips, only grow in length

Question 12

fungal spores

Answer 12

asexually or sexually, always haploid, produce hyphae

Question 13

non-chytrid fungal life cycle - haploid stages

Answer 13

hyphae and spores

Question 14

non-chytrid fungal life cycle - diploid stage

Answer 14

transient single-celled zygote formed during sexual reproduction, undergoes meiosis to make haploid spores (do not show alternation of generations)

Question 15

gametes/separate sexes

Answer 15

not present in fungi, zygote created by any haploid nuclei

Question 16

sex in fungi

Answer 16

1. plasmogamy –> heterokaryon

2. karyogamy

Question 17

plasmogamy

Answer 17

fusion of cytoplasm of genetically different individuals, nuclei are separate

Question 18

heterokaryon

Answer 18

a mycelium with 2 or more different genotypes of separate nuclei, may remain in this state for a long period of time so flaws from one genome can be compensated for by the other

Question 19

dikaryotic state

Answer 19

two genetically distinct nuclei ‘move in together’ to share one hyphal compartment (only in septate hyphae)

Question 20

karyogamy

Answer 20

nuclei fuse, produce 2n zygote

Question 21

“phylum” chytridiomycota

Answer 21

not monophyletic, flagellated stages, gametes, some undergo alternation of generations, have cell walls made of chitin and absorptive mode of nutrition, implicated in global decline of amphibians

Question 22

“phylum” zygomycota

Answer 22

not monophyletic, most look like bread mold, have coenocytic hyphae (except for sexual reproduction structures), engage in sex with different mating type (different chemical markers) when conditions are bad

Question 23

Rhizopus stolonifer

Answer 23

black bread mold, zygomycete

Question 24

sexual reproduction in zygomycota

Answer 24

1. hyphae grow toward each other, will swell and touch if they like each other’s taste
2. gametangia develops
3. gametangia touch (plasmogamy)
4. zygosporangium develops
5. karyogamy produces several 2n zygotes in zygosporangium
6. meiosis and mitosis to produce stalked 1n sporangium
7. sporangium produces spores through mitosis

Question 25

gametangium

Answer 25

small septate region that develops at the tip of each hyphae during sexual reproduction

Question 26

zygosporangium

Answer 26

thick walled, can contain several nuclei from each mating type, resistant to drying

Question 27

phylum glomeromycota

Answer 27

symbiotic relationships with roots of plants, part of mycelium inside and outside roots

Question 28

arbuscular endomycorrhiza

Answer 28

root plus branching hyphae

Question 29

ectomycorrhizae

Answer 29

mycelia do not penetrate roots of cells, non-glomeromycotan

Question 30

phylum ascomycota

Answer 30

sexually produce spores in sac-like asci, septate hyphae with pores for nuclei to pass through, and reproduce asexually by fragmenting tips (conidia)

Question 31

ascocarps

Answer 31

clustered asci

Question 32

conidiophore

Answer 32

structures bearing conidia, used in asexual reproduction

Question 33

ascomycota sexual reproduction

Answer 33

1. hyphae from compatible strains produce swelling with antheridium and ascogonium 2. ascogonium produces mass of dikaryotic hyphae, tips become asci 3. karyogamy within ascus --> 2n zygote 4. meiosis --> 4 1n nuclei 5. mitosis --> 8 nuclei become ascospores

Question 34

antheridium

Answer 34

donates nuclei

Question 35

ascogonium

Answer 35

receives nuclei and creates ascus

Question 36

phylum basidiomycota

Answer 36

sexual structures are mushrooms and toadstools, decompose lignin and other plant matter, plant parasites, septate hyphae not permeable to nuclei, asexual rare/absent

Question 37

basidiomycota sexual reproduction

Answer 37

long-lived dikaryotic mycelium, produce basidiocarps

Question 38

basidiocarps

Answer 38

sexual fruiting bodies produced when environmental conditions are good, cap contains thin vertical sheets of tissue called gills, gills lined with millions of basidia

Question 39

basidia

Answer 39

diploid when young, when mature base topped with 4 basidiospores containing 1 haploid nuclei from meiosis

Question 40

4 fungal lifestyles (evolved independently, not monophyletic)

Answer 40

1. molds 2. yeasts 3. mycorrhizae 4. lichens

Question 41

molds

Answer 41

only reproduce asexually (fungi imperfecti)

Question 42

fungi imperfecti

Answer 42

fungi in which only a mold-type growth form is known

Question 43

yeasts

Answer 43

unicellular, reproduce asexually by budding

Question 44

mycorrhizae

Answer 44

mutualistic symbioses of plant roots and fungi, fungus helps plant absorb minerals from soil, plant gives fungus carbohydrates

Question 45

lichens

Answer 45

symbiotic mixture of fungal hyphae and a photosynthetic partner, asexual reproduction occurs through soredia, fungi can have lichenized and non-lichenized versions

Question 46

soredia

Answer 46

hyphae clasping algal/cyanobacterial cell