Lec 9: Fungal Biology

Question 1

Characteristics of Fungi

Answer 1

Eukaryotic

Basic unit: hypha

Hyphal cell walls composed of chitin and glucan

Heterotrophic and osmototrophic nutrition

Produce spores

Most are non-motile

Simple to complex life cycles involving vegetative growth with asexual and/or sexual reproduction

Question 2

Eukaryotic

Answer 2

Cells contain: nucleus, mitochondria, ER, ribosomes, microtubules, microfilaments

Cell bounded by plasma membrane and cell wall

Question 3

Hyphae

Answer 3

Tubular branching filament

Mass of branching hyphae = mycelium (type of thallus: body or vegetative structure of fungus)

Aseptate (coenocytic): protoplasm streams through hyphae

Septate: septum with pores -> streaming

Question 4

Heterotrophic

Answer 4

Use reduced, preformed organic molecules

Question 5

Osmototrophic

Answer 5

Soluble nutrients absorbed through cytoplasmic membrane

Question 6

Spores

Answer 6

Sexual and asexual spores

Asexually on mycelium

Sexually following mating

Question 7

Major fungal groups

Answer 7

Chytridiomycota

Zygomycota

Glomeromycota

Ascomycota

Basidiomycota

Microsporidia

Question 8

Asexual reproduction among fungi

Answer 8

Hyphal growth

Asexual spore formation

Budding (yeasts)

Question 9

Hyphal growth (vegetative growth)

Answer 9

Hyphal fragments transplanted or broken from body of fungus -> continue to grow

Question 10

Asexual spore formation

Answer 10

Types:

Sporangiospores ( produced in membrane-enclosed structure: sporangium)

Conidiospores (spores born on tips or sides - not enclosed in membrane)

Question 11

Zygomycota

Answer 11

‘Zygomycetes’

Most are saprophytes

Industrial importance: production of foods, antibiotics & other drugs, meat tenderiser, and yellow food colourising

Question 12

Ascomycota

Answer 12

Ascomycetes, cup fungi (ascocarp)

Most are saphrophyte

Few are plant and animal pathogen

Terrestrial & aquatic

Include yeasts & truffles

Question 13

Characteristics of ascomycota

Answer 13

Usually septate hyphae

Sexual reproduction: heterothallic, produce ascospores borne in asci on ascocarp

Asexual reproduction: formation conidiospores (conidia) on conidiophores

Question 14

Basidiomycota

Answer 14

Basidiomycetes, club fungi (zygote form)

Most are saprophytes

Dew are plant and animal pathogens

Primarily pathogens

Primarily terrestrial

Include edible mushrooms

Many produce toxic/hallucinogenic compounds (mycotoxicosis)

Question 15

Characteristics of basidiomycota

Answer 15

Usually septate hyphae

Sexual reproduction: heterothallic, produce basidiospores borne in basidia on basidiocarps

Asexual reproduction: rare

Question 16

Roles of fungi

Answer 16

Decomposers

Disease agents

Symbiosis

Products and industry

Question 17

Decomposers

Answer 17

Break down complex macromolecules to simple molecules

Mineralise organic matter, returning important nutrients to environment

Convert organic matter into fungal biomass -> food for other organisms

Question 18

Disease agents

Answer 18

Plants, animals and humans (superficial, cutaneous, subcutaneous, systemic infections)

Question 19

Symbiosis

Answer 19

Lichens: association between fungus (ascomycete) + alga or cyanobacterium

Mycorrhizae: association between fungus (ascomycete or basidiomycete) + plant

Question 20

Products and industry

Answer 20

Foods/beverages

Industrial chemicals- organic acids and alcohols

Pharmaceuticals: antibiotics