Chapter 31 - Fungi

Question 1

Fungi are most related to what kingdom?

Answer 1

Animals

Question 2

What substance is found in the cell walls of fungi? And is also found in what other organisms?

Answer 2

• chitin

- found in exoskeletons of arthropods

Question 3

Hyphae

Answer 3

Individual filaments in the body of the fungus

Question 4

Mycelium

Answer 4

A mass of connected hyphae in the body of the fungus

Question 5

Monokaryotic

Answer 5

• (separate)

* hyphae w/one nucleus

Question 6

Dikaryotic

Answer 6

Hyphae w/2 nuclei

Question 7

Heterokaryotic

Answer 7

Nuclei from 2 genetically distinct individuals

Question 8

Homokaryotic

Answer 8

Nuclei from genetically similar individuals

Question 9

Coenocytic

Answer 9

Hyphae made up of a continuous cytoplasmic mass w/hundreds or thousands of nuclei

Question 10

What is the relevant unit of reproduction in fungi?

Answer 10

The nucleus; not the cell

Question 11

How do fungi take in nutrients?

Answer 11

• heterotrophic

* excrete enzymes for external digestion and then absorb digested products (saprobic)

Question 12

How does sexual reproduction occur in fungi?

Answer 12

• involves fusion of hyphae from 2 compatible mating types or hyphae from the same fungus
• compatibly is determined by pheromones released by hyphae

Question 13

Plasmogamy

Answer 13

Union of the cytoplasms of two parent mycelia followed by

Question 14

Karygomy

Answer 14

Fusion of haploid nuclei from the parent mycelia; produces diploid nucleus

Question 15

How do fungi reproduce asexually?

Answer 15

• spores spread; dispersed by wind

* yeast (unicellular example) can reproduce by budding

Question 16

Features of chytridiomycota

Answer 16

• fungi w/flagellated zoospores
• aquatic, flagellated fungi
• can be plant pathogens
• can be parasites of other fungi, protists, and animals

Question 17

Chytrids have been implicated in the die-off of what organisms around the world?

Answer 17

Amphibians

Question 18

Key characteristics of zygomycota

Answer 18

• produces zygotes
• Rhizopus found growing in moist bread or fruit
• the simple type feeds on sugars

Question 19

Sexual Reproductive cycle of Rhizopus

Answer 19

• plasmogamy produces a sturdy structure called a zygosporangium
• karyogamy entails fusion of haploid resulting in diploid zygote nuclei

Question 20

Asexual reproductive cycle of Rhizopus

Answer 20

• more common

* sporangia release thin-walled haploid spores which may be dispersed by wind

Question 21

Characteristics of Glomeromycota

Answer 21

• can not survive w/out a host plant
• mutualism is involved where the fungus provides minerals (especially phosphorus) to the plant and the plant provided carbohydrates to the fungus
• grows within root cells of most trees & herbaceous plants; these hyphae are called arbuscular mycorrhizae

Question 22

Characteristics of Ascomycota

Answer 22

• make up 75% of known fungi
• examples include yeast, common molds, morels, cup fungi, and truffles
• this phylum also includes plant pathogens such as those that cause chestnut blight and Dutch elm disease

Question 23

How do yeasts reproduce?

Answer 23

Cell fission or budding

Question 24

Characteristics of basidiomycota

Answer 24

• visible reproductive structure = basidiocarp
• EX. Mushrooms, toadstools, puffballs, shelf fungi (breaks down lignin in wood), etc
• sexually reproduce w/basidia; gills on the undersurface of the mushroom cap produce numbers of spores

Question 25

What 2 substances are fungi able to breakdown

Answer 25

Lignin and cellulose which then releases carbon, nitrogen, and phosphorus resulting in making these elements available to other organisms

Question 26

Obligate Symbiosis

Answer 26

* essential to survival | * they have to have that relationship w another organism to live

Question 27

Facultative symbiosis

Answer 27

• fungus can survive w out a host

Question 28

Pathogen

Answer 28

* fungus benefits and host is harmed or killed | * they can cause disease

Question 29

Parasite

Answer 29

* fungus benefits and host is harmed or killed | * does not cause disease except in extreme situations

Question 30

Commensalism

Answer 30

• only one partner benefits and the other is unaffected

Question 31

Mutualism

Answer 31

• both the fungus and host benefit

Question 32

Endophytes

Answer 32

* live inside plants and may protect them from parasites | * some produce chemical toxins or other deterrents to keep things away

Question 33

Lichens

Answer 33

* are an example of symbiosis * composer of a fungus (usually ascomycete) along w/Cyanobacteria, green algae, or both * can live in very harsh habitats * usually the first to colonize an area * break down rocks and help prepare for invasion of other organisms * produce bright pigments (some used as dyes) * some are used to indicated air quality as they can absorb rain and dew * few are found in or near cities and as pollution decreases, their population increases

Question 34

Mycorrhizae

Answer 34

* Associated w/roots of plants * means fungus roots * fungal hyphae increases amount of contact w/soil & surface area for absorption * aid in direct transfer of phosphorus, zinc, copper, and other minerals

Question 35

Haustoria

Answer 35

Specialized hyphae used to extract from or exchange nutrients w plant host

Question 36

Arbuscular Mycorrhizae

Answer 36

Grow within the outer cells of the plant root

Question 37

Ectomycorrhizae

Answer 37

Surround root cells but do not penetrate them

Question 38

Examples of symbiosis between fungi and animals

Answer 38

* ruminant animals have fungi in their gut | * ants provide food for fungi and then eat fungi

Question 39

Fusarium

Answer 39

* grows on spoiled food | * produces vomitoxin that can cause brain damage in animals/humans in sw us

Question 40

Aspergillus

Answer 40

* Produces aflatoxins that are very carcinogenic (cancerous) * strains are on corn, peanuts, cotton seeds * can damage kidneys & nervous system * considered a bioterrorism agent

Question 41

Corn smut

Answer 41

Damages corn but is not harmful to animals or humans that consume it

Question 42

Ergot

Answer 42

* fungus associated w rye and other cereal grains * an alkaloid toxin is produced & if eaten can cause hallucinations, nervous spasms, gangrene, and burning sensations * lysergic Avis has been isolated from ergot and is used to make LSD * implicated Salem witch trials

Question 43

Why are fungal infections difficult to treat?

Answer 43

They are eukaryotes and antibiotics cannot be used to treat them

Question 44

Examples of fungal diseases

Answer 44

* ringworm * athletes foot * thrush * nail fungus * oral or vaginal infections caused by candida * mold allergies