Chapter 32 reading Flashcards

1
Q

What is the reason for their being a lack of dead organic matter (d.o.m.) in tropical rainforest (and other ecosystems)?

A

fungi - they are responsible for decomposition of plant and animal tissues on land

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2
Q

What are features of fungi regarding consumption and access to energy?

A

depend on pre formed molecules for both carbon and energy
no organs, so absorb organic molecules directly thru cell walls

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3
Q

What are two major problems with no organs and reliance on pre formed carbon and energy for fungi?

A

more complicated molecules do no pass thru the cell wall
no means of locomotion

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4
Q

how do fungi deal with inability of larger molecules to pass thru cell wall?

A

fungi secrete enzymes that break down starch or cellulose

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5
Q

how do fungi deal with inability to move?

A

use process of growth to find nourishment - hyphae

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6
Q

What are hyphae?

A

highly branched, multicellular filaments, long & thin - provides large surface area for absorbing nutrients

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7
Q

What is mycelium?

A

the network of branching hyphae that forms the body of a fungus

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8
Q

Where are enzymes for breakdown of starch and cellulose secreted?

A

tip of the hyphae

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9
Q

What is the material of cell wall of hyphae?

A

chitin

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10
Q

What does chitin provide hyphae with?

A

a strong but flexible cell wall

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11
Q

What is chitin?

A

modified polysaccharide that contains nitrogen

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12
Q

What do hyphae and the mycelium formation allow for fungi to do?

A

grow between resource patches and produce reproductive structures like mushroom above ground

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13
Q

What do molecules that are absorbed by hyphae do? (chain reaction)

A

they drive osmosis which increases turgor pressure which increases growth and respiration in hyphae which decreases turgor pressure
= bulk flow

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14
Q

What does a continuous stream of cytoplasm in fungi do?

A

allows for movement of materials by bulk flow in mycelium

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15
Q

What are septa?

A

partitions between cell, has pores that allow transport of solutes along hypha

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16
Q

What is the function of septa?

A

when hyphae are damaged, sealing mechanism plugs pores preventing loss of pressurised cytoplasm

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17
Q

What is an example of a fungi that does not produce hyphae?

A

yeast

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18
Q

What is yeast?

A

single-celled fungi in moist, nutrient rich environments

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19
Q

Why don’t yeast have hyphae?

A

lost from descendants by convergent evolution

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20
Q

How do yeast divide?

A

by budding - a small outgrowth that increases in size and eventually breaks off to form a new cell

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21
Q

Where is yeast commonly found?

A

on surfaces of plants and sometimes on surfaces of animal gut

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22
Q

WHat are uses of yeast?

A

leavened bread, alcoholic bevs, in lab studies of genetics

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23
Q

What do fungi convert d.o.m. too?

A

CO2 and H2O

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24
Q

What do fungi do for carbon and life cycle?

A

keeps biological carbon cycle in balance and returns nutrients to the soil where they are able to support new plant growth

25
Q

What are the advantages that fungi have to live on forest floor?

A

hyphae can expand fungi coverage > bacteria by flagellum
hyphae can break into interior of a food source (break down tree stems)
wood-rotting fungi produce enzymes that degrade lignin

26
Q

How do fungal pathogens infect plants?

A

thru woods, stomata, or directly thru epidermal cells

27
Q

What are fungal pathogens that cause agricultural losses?

A

ruts, smuts, and molds

28
Q

What makes fungal pathogens good at invasion?

A

host specificity

29
Q

What is an adaptation of invasion for Vascular wilt fungi?

A

hyphae through xylem vessels - makes it through entire plant

30
Q

What species have vascular wilt fungi almost made extinct?

A

American Elm trees

31
Q

How do aboveground plant infections usually spread?

A

via fungal spores - carried by wind or on insect bodies

32
Q

How do belowground plant infections spread?

A

by hyphae that penetrate roots of plants

33
Q

How can fungi exploit living-moving organisms?

A

by trapping them, sticky traps with hyphae, some lasso prey with rings that inflate and trap anything inside (like Nematodes)

34
Q

What type of animals do fungi usually infect?

A

fish and amphibians (cold-body temp) so also bat species in winter hibernation

35
Q

What is mycorrhizae?

A

symbiotic association with plants - provide roots with nutrients (P&N), get carbohydrates from host

36
Q

What is ectomycorrhizae?

A

surround but do not penetrate root cells

37
Q

What is endomycorrhizae?

A

hyphae penetrate into root cells and produce highly branched structures for large surface area for nutrient exchange (form a monophyletic group)

38
Q

What are endophytes?

A

live within leaves - grow within cell walls and in spaces between cells - help improve plant growth during stressful conditions or produce chemicals that deter pathogenic invasion or herbivorous insect consumption

39
Q

What is a lichen?

A

symbioses between a fungus and a photosynthetic microorganism (green alga or a cyanobacteria)

40
Q

What is lichen make up?

A

bulk fungal hyphae
phtosoynthetic microorganism = layer underneath

41
Q

What do hyphae do for lichen?

A

anchor to tree or rock
uptake and retention of water and nutrients to produce chemicals that protect organism against excess light and herbivorous animals

42
Q

What does the green algae or cyanobacteria provide in lichen?

A

source of reduced carbon, cyanobacteria can fix nitrogen from atmosphere

43
Q

How do lichens spread?

A

usually by fragmentation or thru formation of dispersal units consisting of single photosynthetic cell surrounded by hyphae

44
Q

how are lichens adapted to be among the first colonizers of lava flows and barren lands post glacial retreat?

A

they can obtain nutrients from rainfall or secreting organic acids that release some nutrients from rocky substances

45
Q

What are lichens tolerant to?

A

drying out, desiccation, fluctuations in temp and light

46
Q

What are lichens sensitive to?

A

air pollution (SO2 esepcially) - so can be used as an indicator for industrial polllution

47
Q

How do fungi reproduce?

A

asexual or sexual, through fungal spores

48
Q

What increases fungi chances of reproducing?

A

large numbers of spores produced

49
Q

What is sexual reproduction spore formation by?

A

meiotic cell division

50
Q

What is asexual reproduction spore formation by?

A

mitotic cell division - produced by sporangia that form at ends of erect hyphae

51
Q

What are fruiting bodies?

A

structures that release sexually produced spores into the air for dispersal (e.g. mushrooms, stinkhorns, puffballs, bracket fungi, truffles)

52
Q

What allows for good dispersal for fungi?

A

elevation and forcible ejection

53
Q

What are the 3/4 stages in the asexual cycle? are they haploid or diploid?

A

all haploid (n)
germination - mycelium formation - spore formation - dispersal …

54
Q

What are the 8/9 stages in sexual cycle? are they haploid or diploid or else?

A

Germination (n) - mycelium formation (n) - Plasmogamy (formation of cytoplasm (n) - Heterokaryotic cell (unfused nuclei from different spores) (intermediate stage) - karyogamy (fusion of nuclei) ( intermediate to 2n) - zygote - meiosis (2n to n) - spores (n) - dispersal (n) - to start…

55
Q

What is the heterokaryotic stage?

A

nuclei from two parental hyphae remains distinct and continues to divide eventually nuclei fuse and form a zygote

56
Q

What is a dikaryote?

A

cells with 2 genetically distinct haploid nuclei

57
Q

What are mating types?

A

fungi have different mating types that are genetically determined which prevent self-fertilization

58
Q

What is parasexuality?

A

crossing over during mitosis is thought to provide genetic diversity in asexual fungi