Chapter 32 reading

Question 1

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

Answer 1

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

Question 2

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

Answer 2

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

Question 3

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

Answer 3

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

Question 4

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

Answer 4

fungi secrete enzymes that break down starch or cellulose

Question 5

how do fungi deal with inability to move?

Answer 5

use process of growth to find nourishment - hyphae

Question 6

What are hyphae?

Answer 6

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

Question 7

What is mycelium?

Answer 7

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

Question 8

Where are enzymes for breakdown of starch and cellulose secreted?

Answer 8

tip of the hyphae

Question 9

What is the material of cell wall of hyphae?

Answer 9

chitin

Question 10

What does chitin provide hyphae with?

Answer 10

a strong but flexible cell wall

Question 11

What is chitin?

Answer 11

modified polysaccharide that contains nitrogen

Question 12

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

Answer 12

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

Question 13

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

Answer 13

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

Question 14

What does a continuous stream of cytoplasm in fungi do?

Answer 14

allows for movement of materials by bulk flow in mycelium

Question 15

What are septa?

Answer 15

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

Question 16

What is the function of septa?

Answer 16

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

Question 17

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

Answer 17

yeast

Question 18

What is yeast?

Answer 18

single-celled fungi in moist, nutrient rich environments

Question 19

Why don’t yeast have hyphae?

Answer 19

lost from descendants by convergent evolution

Question 20

How do yeast divide?

Answer 20

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

Question 21

Where is yeast commonly found?

Answer 21

on surfaces of plants and sometimes on surfaces of animal gut

Question 22

WHat are uses of yeast?

Answer 22

leavened bread, alcoholic bevs, in lab studies of genetics

Question 23

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

Answer 23

CO2 and H2O

Question 24

What do fungi do for carbon and life cycle?

Answer 24

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

Question 25

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

Answer 25

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

Question 26

How do fungal pathogens infect plants?

Answer 26

thru woods, stomata, or directly thru epidermal cells

Question 27

What are fungal pathogens that cause agricultural losses?

Answer 27

ruts, smuts, and molds

Question 28

What makes fungal pathogens good at invasion?

Answer 28

host specificity

Question 29

What is an adaptation of invasion for Vascular wilt fungi?

Answer 29

hyphae through xylem vessels - makes it through entire plant

Question 30

What species have vascular wilt fungi almost made extinct?

Answer 30

American Elm trees

Question 31

How do aboveground plant infections usually spread?

Answer 31

via fungal spores - carried by wind or on insect bodies

Question 32

How do belowground plant infections spread?

Answer 32

by hyphae that penetrate roots of plants

Question 33

How can fungi exploit living-moving organisms?

Answer 33

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

Question 34

What type of animals do fungi usually infect?

Answer 34

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

Question 35

What is mycorrhizae?

Answer 35

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

Question 36

What is ectomycorrhizae?

Answer 36

surround but do not penetrate root cells

Question 37

What is endomycorrhizae?

Answer 37

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

Question 38

What are endophytes?

Answer 38

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

Question 39

What is a lichen?

Answer 39

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

Question 40

What is lichen make up?

Answer 40

bulk fungal hyphae phtosoynthetic microorganism = layer underneath

Question 41

What do hyphae do for lichen?

Answer 41

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

Question 42

What does the green algae or cyanobacteria provide in lichen?

Answer 42

source of reduced carbon, cyanobacteria can fix nitrogen from atmosphere

Question 43

How do lichens spread?

Answer 43

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

Question 44

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

Answer 44

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

Question 45

What are lichens tolerant to?

Answer 45

drying out, desiccation, fluctuations in temp and light

Question 46

What are lichens sensitive to?

Answer 46

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

Question 47

How do fungi reproduce?

Answer 47

asexual or sexual, through fungal spores

Question 48

What increases fungi chances of reproducing?

Answer 48

large numbers of spores produced

Question 49

What is sexual reproduction spore formation by?

Answer 49

meiotic cell division

Question 50

What is asexual reproduction spore formation by?

Answer 50

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

Question 51

What are fruiting bodies?

Answer 51

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

Question 52

What allows for good dispersal for fungi?

Answer 52

elevation and forcible ejection

Question 53

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

Answer 53

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

Question 54

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

Answer 54

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...

Question 55

What is the heterokaryotic stage?

Answer 55

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

Question 56

What is a dikaryote?

Answer 56

cells with 2 genetically distinct haploid nuclei

Question 57

What are mating types?

Answer 57

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

Question 58

What is parasexuality?

Answer 58

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