Ch. 24 Fungi

Question 1

Several characters were originally used to unite and define fungi:

Answer 1

• complete heterotrophy with no photosynthetic stages
• formation of spores
• the presence of chitin in their walls
• lack of complex bodies with organs

Question 2

All fungi are completely ___

Answer 2

Heterotrophic

Question 3

Fungi must obtain

Answer 3

Soluble nutrients from the environment or from living, dying, or dead organisms

Question 4

Fungi are subdivided into three groups:

Answer 4

Biotrophs, necrotrophs, and saprotrophs

Question 5

Biotrophs

Answer 5

• parasites

- draw nutrients slowly from living hosts, often without killing them

Question 6

Necrotrophs

Answer 6

Attack living hosts so virulently that they kill the hosts and then absorb released nutrients

Question 7

Saprotrophs

Answer 7

Attack organisms after they have died from other causes

Question 8

Extracellular digestion

Answer 8

Secrete digestive enzymes that attack host polymers, converting them to sugars, amino acids, and lipids that can be absorbed

Question 9

Fungi, along with most bacteria, are agents of..

Answer 9

Decay, rot, spoilage, and decomposition

Question 10

Necrotrophs secrete ___ that kill host cells

Answer 10

Toxins

Question 11

Excessive levels of ___ are involved in many fungus-induced diseases

Answer 11

Plant hormones

Question 12

Plant hormone may be produced and secreted by the fungus, or

Answer 12

The fungus induces the plant to produce increased levels of its own hormones

Question 13

Many plants produce ___, lipid-like or phenolic compounds, in response to attack by fungi, bacteria, and even nematodes.

Answer 13

Phytoalexins

Question 14

The common essential microelements are

Answer 14

Iron, zinc, copper, manganese, molybdenum, and either calcium or strontium

Question 15

Virtually all fungi absorb and assimilate ___

Answer 15

Ammonium

Question 16

The bodies of all fungi, except unicellular ones, are ___

Answer 16

Filamentous

Question 17

Hyphae

Answer 17

Individual filaments

Question 18

Mycelium

Answer 18

Hyphae branch profusely, forming this network

Question 19

Fungal cells are ___

Answer 19

Eukaryotic

Question 20

The innermost cell wall later is rich in ___, which provides strength

Answer 20

Chitin

Question 21

At one time, ___ and ___ were considered parts of the plant kingdom

Answer 21

Fungi and bacteria

Question 22

An important aspect of hyphal walls is the nature of the ___ or __

Answer 22

Cross walls or septa

Question 23

The primary selective advantage of septa appears to be what rather than compartmentalization of hyphae into distinct cells?

Answer 23

Damage control

Question 24

Fungal nuclei are extremely ___

Answer 24

Small

Question 25

___ in most species of fungi is very uniform, showing little differentiation into euchromatin and heterochromatin

Answer 25

Chromatin

Question 26

During mitosis, the spindle forms inside the nucleus, which remains quite distinct because ..

Answer 26

The nuclear envelope does not break down as it does in plants and animals

Question 27

During ___, the nucleus elongates and the nuclear envelope stretches

Answer 27

Anaphase

Question 28

In some species, the nucleolus is ejected from the nuclear during ___, whereas in others, or remains intact and passes to one of the new nuclei

Answer 28

Prophase

Question 29

In ascomycetes and basidiomycetes, but not in the other fungi, some mycelia form a large, compact, highly organized structure called a ___ which is the principle means of producing spores sexually

Answer 29

Fruiting body

Question 30

The outermost surface hyphae are often slender and have thick walls impregnated with pigments called ___

Answer 30

Melanins

Question 31

Within large fruiting bodies, especially bracket fungi, are three types of hyphae:

Answer 31

- generative hyphae - skeletal hyphae - binding hyphae

Question 32

Generative hyphae

Answer 32

Thin walled and produce spores

Question 33

Skeletal hyphae

Answer 33

Thick wall and unbranched

Question 34

Binding hyphae

Answer 34

Thick walled but are highly and irregularly branched

Question 35

A universal character of fungi is their formation of ___, resistant resting stages that are the primary means of reproduction, dispersal, and survival

Answer 35

Spores

Question 36

Spores are produced __ and ___

Answer 36

Asexually and sexually

Question 37

In zygomycetes, asexual spores are typically ___

Answer 37

Sporangiospores

Question 38

Sporangiospores

Answer 38

Spores that form inside the large swollen tip of a hypha

Question 39

In ascomycetes, basidiomycetes, and deuteromycetes, asexual spores are more often produced as ___

Answer 39

Conidia

Question 40

Conidia

Answer 40

Spores that do not form inside a sporangium

Question 41

Sexual reproduction in most fungi

Answer 41

Hyphae of one mycelium fuse with hyphae of a different mycelium if the two are compatible; these are opposite mating types, designated as + and -

Question 42

Plasmogamy

Answer 42

The fusion of two hyphae

Question 43

Plasmogamy is usually not followed immediately by ___

Answer 43

Kayogamy

Question 44

Karyogamy

Answer 44

Doesn't occur ultimately, in a special reproductive structure characteristic of each clade

Question 45

Although fungi are rather simple morphologically, they are diverse in their ___, ___, and ___.

Answer 45

Metabolism, energy, and life cycles

Question 46

Many fungi are capable of either ___ or ___ growth

Answer 46

Aerobic or anaerobic growth

Question 47

As with bacteria, some fungi are extreme ___, growing best at temperatures up to 50C but poorly at or below 20C.

Answer 47

Thermophiles

Question 48

___ fungi are those that grow best in cold conditions, in the range of -10C to -15C

Answer 48

Psychrophilous fungi

Question 49

___ fungi grow on "dry" substrates, dryness being due to no lack of water but instead to a high concentration of solute or other materials that bind waters firmly

Answer 49

Xerophilous

Question 50

___ are distinct from true fungi

Answer 50

Slime molds

Question 51

In true slime molds, the body is a large mass of ___ containing thousands of nulei, all in the same cytoplasm

Answer 51

Protoplasm

Question 52

This mass of protoplasm, called a ___, is capable of migrating over a substrate, but is so large that it is easily visible to the naked she o

Answer 52

Plasmodium

Question 53

Most ___ have chitinous walls like other fungi, but they are distinct in having ___.

Answer 53

- Chytridiomycetes | - flagellated motile cells

Question 54

All groups are primarily ___, with most species living in streams, ponds, or lakes

Answer 54

Water molds

Question 55

___ live on various substrates, some being parasitic on other water molds and algae and others saprotrophic on dead insects and plant parts

Answer 55

Chytrids

Question 56

Zygomycetes

Answer 56

- approx 600 described species - most are terrestrial and live in decaying plant and animal matter in soil or forest litter - mold on stale bread, Rhizopus stolonifer - simple mycelia composed of branched coenocytic hyphae; complex fruiting bodies were not formed - sexual production occurs in zygomycetes if hyphae of one individual come close to those of another of compatible mating strain

Question 57

Zygomycetes are characterized by their method of sexual reproduction, which results in..

Answer 57

A large zygosporangium with mandate dormant nuclei

Question 58

Ascomycetes

Answer 58

- all have asci - thought to have evolved from a zygomycete-like ancestor - form ascocarp

Question 59

Asci

Answer 59

Large sac-like cells in which Karyogamy and meiosis occur and in which the resulting meiospores form

Question 60

Ascocarp

Answer 60

A rather organized, pseudo-parenchymatous fruiting body

Question 61

Ascomycetes asexual reproduction occurs by..

Answer 61

Formation of Conidia

Question 62

Sexual reproduction in ascomycetes

Answer 62

Two compatible hyphae that happen to approach each other each produce special short, multinucleate branches: ascogonium and antheridium - nuclei pair but do not fuse (dikaryotic) - no sperms, eggs, or zygotes, but syngamy, meiosis, and crossing-over do occur

Question 63

Ascocarps of three types:

Answer 63

- the cleistothecium is spherical with no opening; spores are released upon decay - a perithecium is a flask-shaped ascocarp that releases ascospores through a narrow opening - apothecia are disk or saucer shaped

Question 64

Basidiomycetes

Answer 64

Mushrooms, puffballs, and bracket fungi | - delimited by a synapomorphy, the basidium

Question 65

Basidium

Answer 65

Terminal cell of a reproductive hypha of a basidiomycete; in it, the two compatible nuclei fuse and then immodestly undergo meiosis and crossing-over

Question 66

Basidiospores do not form inside the basidium, however; instead four tiny projections form, called ___

Answer 66

Sterigmata

Question 67

Imperfect fungi

Answer 67

- deuteromycetes - able to persist indefinitely using only asexual means of propagation - artificial classification

Question 68

____ has made it possible to examine the structure of their septa

Answer 68

Electron microscopy

Question 69

Lichens

Answer 69

Association of a fungus with an alga or a cyanobacterium | - symbiotic

Question 70

Symbiotic relationship

Answer 70

Each organism benefits

Question 71

Soredia

Answer 71

Small masses of hyphae and autotrophic cells

Question 72

Mycorrhizae

Answer 72

Symbiotic association of roots and soil fungi

Question 73

Fungus-plant association occurring in orchids

Answer 73

Appears as if the orchid is parasitizing the fungus because the fungi are capable of living freely without the orchid

Question 74

Fungi mostly interact with living plants as ____

Answer 74

Disease organisms

Question 75

Brown rot of stone fruits

Answer 75

Peaches, plums, and cherries are attacked by the ascomycete Monilinia fructicola which causes brown rot - after Conidia germinate, hyphae invade the fruit, dissolve the middle lamella, and cause tissues to become soft and brown

Question 76

The fruit finally rots and shrivels, becoming a ___

Answer 76

Mummy

Question 77

Rusts and smuts

Answer 77

- serious plant diseases caused by basidiomycete - rusts (order Uredinales) - smuts (order Ustilaginales) - can attack hosts so virulently that they kill the plant - most notorious species is the stem rust fungus Puccinia graminis, which occurs in many forms

Question 78

The life cycle of P. Graminis is..

Answer 78

Complex but excellent for understanding many aspects of fungal biology - heteroecious species - this life cycle has the basic features of basidiomycetes, plus some additional ones

Question 79

Heteroecious species

Answer 79

It requires two different living hosts to complete its life cycle