bio test chapter 31

Kingdom Fungi

a kingdom of mostly multicellular eukaryotic organisms that are heterotrophs and absorb nutrients from their environment

heterotrophs

organisms that cannot make their own food and must obtain nutrients from other sources

hyphae

threadlike filaments of a fungus made of cytoplasm surrounded by a cell wall;

chitin

a strong, flexible polysaccharide that makes up fungal cell walls and insect exoskeletons

mycelium

an interwoven network of hyphae that forms the main body and feeding structure of a fungus

haustoria

specialized hyphae that penetrate host tissues to absorb nutrients

opisthokonts

a clade that includes fungi, animals, and certain protists with a shared evolutionary ancestry

nucleariids

unicellular protists that are the closest relatives of fungi

choanoflagellates

unicellular protists that are the closest relatives of animals

mycorrhizae

mutualistic associations between fungal hyphae and plant roots

lichens

symbiotic associations between fungi and photosynthetic organisms such as algae or cyanobacteria

1. What are fungi?

Fungi are eukaryotic organisms that are heterotrophs and obtain nutrients by absorbing them after externally digesting organic material;

1a. What kingdom do fungi belong to?

Fungi belong to Kingdom Fungi;

1b. How are fungi different from plants and animals?

Unlike plants, fungi are heterotrophs and acquire their nutrients by absorption.

Unlike animals, a fungus digests food outside its body by secreting powerful digestive enzymes that decompose complex molecules to simpler compounds that the fungus can absorb.

1c. What are the various ecological roles of fungi?

Fungi function as decomposers, parasites, and mutualists in ecosystems;

1d. What are unicellular fungi called?

Unicellular fungi are called yeasts;

2. Describe the basic structure of a multicellular fungus.

A multicellular fungus is composed of branching hyphae that form a mycelium, which acts as the feeding structure

2a. What are fungal cell walls composed of?

Fungal cell walls are composed of chitin

2b. What are hyphae?

Hyphae are microscopic filaments that make up the body of a fungus;

2c. What is a mycelium?

A mycelium is a network of hyphae that increases surface area for nutrient absorption;

2d. What is the function of haustoria?

Haustoria penetrate host cells and absorb nutrients directly from the host; mycorrhizal fungi and some parasitic fungi has specialized hyphae called haustoria

3a. What is the function of a mushroom?

A mushroom is a reproductive structure that produces and disperses spores;

3b. How do yeasts reproduce?

Yeasts reproduce asexually by budding, where a small cell grows and detaches from the parent cell;

4. Are fungi more closely related to plants or animals?

Fungi are more closely related to animals than plants;

4a. What clade do fungi, animals, and their protistan relatives belong to?

They belong to the opisthokonts clade;

4b. In what supergroup are fungi and animals classified?

They are classified in the supergroup Unikonta;

4c. What type of protist are fungi more closely related to?

Fungi are more closely related to nucleariids;

4d. What type of protist are animals more closely related to?

Animals are more closely related to choanoflagellates;

5. Why are fungi effective decomposers?

Fungi are effective decomposers because their hyphae penetrate organic material and secrete enzymes that break down complex substances like cellulose and lignin into absorbable nutrients;

6. Describe the mutualistic relationship between fungi and the roots of plants.

Fungi form mycorrhizae with plant roots, where fungi provide minerals and water while plants provide sugars;

6a. What are lichens? What are mycorrhizal fungi?

Lichens are symbiotic partnerships between fungi and algae or cyanobacteria, while mycorrhizal fungi form mutualistic relationships with plant roots;

6b. What kind of mutualistic relationships do fungi have with animals?

Fungi help animals digest plant material, such as in the guts of cows, and some ants farm fungi for food;

6c. Parasitic relationships of fungi;

Fungi can infect plants causing crop diseases and can infect animals causing conditions like athlete's foot or yeast infections;

6d. Commercial uses of fungi;

Fungi are used to produce antibiotics, decompose waste, and make foods such as bread, cheese, beer, and wine;