Lecture 14

Question 1

decomposers

Answer 1

break down complex organic compounds into inorganic

(mineral) forms, necessary for nutrient cycling otherwise all carbon & nitrogen would be locked up in dead tissues

Question 2

lignin decomposition

Answer 2

fungi more important than bacteria in breaking down lignin, most soil-dwelling fungi make their living by decomposing plant matter

Question 3

fairy rings

Answer 3

result of outward growth of decomposer hyphae, release of nutrients from detritus by fungi is greatest at leading
edge

Question 4

2 ways lichens break down solid rock

Answer 4

1. produce carbonic acid

2. insinuate hyphae into cracks, swelling of hyphae when wet can further split rock

Question 5

endolithic lichens

Answer 5

grow under surface of rock (except for fruiting bodies)

Question 6

ectomycorrhizae

Answer 6

2000 spp, hyphae penetrate root but do not enter cells

includes all conifers, willows, birches, very important in boreal forest

Question 7

endomycorrhizae

Answer 7

all other spp, hyphae penetrate cells

Question 8

mycorrhizal innoculation

Answer 8

used during reforestation because plants grown with their fungal partner do better than without, especially in poor soil

Question 9

achlorophyllous plants

Answer 9

do not photosynthesize, obtain all carbohydrates from mycorrhizal fungi, fungus is a mycorrhizal associate of a photosynthetic plant as well, distant parasite of host plant and parasite of fungus

Question 10

4 types of plant-parasitic fungi

Answer 10

1. necroses
2. wilting
3. powdery mildews
4. hypertrophy

Question 11

necroses

Answer 11

blights, cankers, and scabs caused by fungi digesting plant tissues

Question 12

wilting

Answer 12

caused by hyphae blocking xylem of plants

Question 13

powdery mildews

Answer 13

fungi coat leaves and fruits, penetrate surface cells with special hyphae

Question 14

hypertrophy

Answer 14

fungi liberate plant hormones that cause excessive tissue growth

Question 15

3 ways fungi prevent reproduction in plants

Answer 15

1. prevent flowering
2. replace seed with own fruiting body
3. replace pollen with fungal spores

Question 16

Dutch Elm Disease

Answer 16

introduced to North America in 1930 in imported elm wood, caused by Ophiostoma ulmi (asco-), vectored by bark beetles, killed most native elms in eastern
North America

Question 17

Chestnut blight

Answer 17

Cryphonectria parasitica (asco-) brought into North America with imported oriental chestnut seedlings in 1904, by 1950’s almost all chestnut trees in North America dead, some trees survived due to hypovirulent fungi

Question 18

hypovirulent fungi

Answer 18

a strain that has been weakened by a virus –> prevent infection by virulent strain by transmitting virus, and making invading fungi also hypovirulent

Question 19

fungi that eat invertebrates

Answer 19

fungi able to digest chitin (old mycelia and chitinous cuticle of arthropods)

Question 20

nematode traps

Answer 20

evolved independently in many soil-dwelling fungi - sticky tabs, detachable rings, strangling ring

Question 21

3 types of mycoses (fungal diseases)

Answer 21

1. cutaneous (outer layers of skin infected)
2. localized subcutaneous (wound infected)
3. systemic (widespread)

Question 22

dermatophytes

Answer 22

fungi that digest keratin and cause cutaneous infections, cause skin diseases called tineas and
ringworms

Question 23

athlete’s foot/jock itch

Answer 23

itching caused by irritating enzymes released by fungi

Question 24

Candida albicans

Answer 24

yeast that causes thrush, causes no harm in gut but colonizes skin in moist conditions

Question 25

histoplasmosis

Answer 25

most common systemic mycosis in N. America, grows on nitrogen-rich substrates (bird droppings, bat guano)

Question 26

immune-compromised people

Answer 26

high risk of mycoses, normally benign fungi can become systemic parasites

Question 27

Agaricus bisporus

Answer 27

(basidio) most commonly cultivated mushroom - button/white

Question 28

truffles

Answer 28

(asco) sought after and caught wild in Europe, subterranean fruiting bodies produce odours that attract female pigs

Question 29

morels

Answer 29

(asco) sought after and caught wild in N. America

Question 30

huitlacoche

Answer 30

corn smut, Mexican delicacy, causes hypertrophic growth of corn ear, eaten before spores form

Question 31

yeast spreads

Answer 31

Marmite, vegemite

Question 32

saccharomyces cereviseae

Answer 32

brewer's and baker's yeast, produces CO2 and ethanol by breaking down sugars, CO2 leavens (raises) dough, ethanol in wine, beer, hard liquors

Question 33

fungi in cheeses

Answer 33

soft cheeses and blue cheeses

Question 34

penicillin

Answer 34

from Penicillium chrysogenum (asco-) fungus, kills | bacteria

Question 35

psilocybin

Answer 35

hallucinogen found in psilocybe and three related genera (basidio-) "magic mushrooms"

Question 36

Amanita muscaria aka fly agaric

Answer 36

(basidio-) produces toxins with hallucinogenic side-effects

Question 37

St. Anthony's fire

Answer 37

violent convulsions, formication (feeling that ants were crawling beneath skin) and gangrene so severe that limbs dropped off, caused by metabolic byproduct of Claviceps purpurea, ergot (asco-)

Question 38

LSD (lysergic acid diethylamide)

Answer 38

precursors came from ergot, produce hallucinations

Question 39

Amanita spp.

Answer 39

(basidio-) several species so toxic that a single bite can result in death