11 Microbial Diversity - Fungi

Question 1

Phylum Chytridiomycota (Chytrids) Habitat

Answer 1

Aquatic and terrestrial

Question 2

Phylum Chytridiomycota (Chytrids) Key features

Answer 2

Mostly unicellular (some are multicellular).

Have zoospores (motile spores with a single flagellum).

Can be saprobes, parasites, or symbiotic.

Chitin in cell walls.

Question 3

Phylum Zygomycota (Zygomycetes) Habitat

Answer 3

Terrestrial (commonly found in soil and decaying matter)

Question 4

Phylum Zygomycota (Zygomycetes) Key features

Answer 4

Coenocytic hyphae (lacking cross-walls).

Reproduce sexually through the formation of zygosporangia (fusion of two gametangia).

Asexual reproduction by sporangia.

Question 5

Phylum Ascomycota (Sac Fungi) Habitat

Answer 5

Diverse - terrestrial and aquatic

Question 6

Phylum Ascomycota (Sac Fungi) Key features

Answer 6

Septate hyphae (hyphae with cross-walls).

Sexual reproduction via the formation of ascospores within a sac-like structure called an ascus.

Asexual reproduction through conidia (asexual spores).

Question 7

Phylum Basidiomycota (Club Fungi) Habitat

Answer 7

Mostly terrestrial - soil and decaying matter

Question 8

Phylum Basidiomycota (Club Fungi) Key features

Answer 8

Septate hyphae.

Sexual reproduction through basidia (club-shaped cells that produce basidiospores).

Fruit bodies (e.g., mushrooms, toadstools) are often formed.

Question 9

Phylum Glomeromycota (Arbuscular Mycorrhizal Fungi) Habitat

Answer 9

Symbiotic with plant roots

Question 10

Phylum Glomeromycota (Arbuscular Mycorrhizal Fungi) Key features

Answer 10

Form arbuscular mycorrhizae, which help plants absorb nutrients (especially phosphorus).

Reproduce through asexual spores.

Important in mutualistic relationships with plants.

Question 11

Structure of Fungi - Hyphae definition

Answer 11

basic unit or a filament that comprise the mycelium

Question 12

Structure of Fungi - Hyphae description

Answer 12

Filamentous structures that form the body of most fungi (except yeasts).

Septate hyphae (with cross-walls) vs. coenocytic hyphae (without cross-walls).

Mycelium is the collective mass of hyphae, forming the vegetative body of the fungus.

Question 13

Structure of fungi - fruit bodies

Answer 13

Specialized reproductive structures (e.g., mushrooms, conidiophores).

In basidiomycetes and ascomycetes, these are the structures that produce spores.

Question 14

Structure of fungi - Sporangium

Answer 14

compartment in which spores are formed. Fungi can reproduce; sexually - spores form via meiosis / asexually - spores form via mitosis

Question 15

Structure of fungi - cell wall

Answer 15

Glucans (polysaccharides) - most abundant component

Chitin (beta 1,4 linked homopolymer) present to provide rigidity and structure

Mannoproteins - involves in cell pathogenesis / evading host immune system

Erogosterol - regulates permeability and fluidity of cell membrane

Question 16

Structure of fungi - hyphal tip

Answer 16

Germ tube that grows by extension - characterised by the addition of new cell wall materials, specifically the apex

Question 17

Fungi nutrition

Answer 17

Fungi are heterotrophic (rely on organic matter for nutrition).

They absorb nutrients through external digestion:
- Secrete enzymes into the environment to break down organic material (e.g., lignin, cellulose).
- Absorb the digested nutrients via their hyphae.

Question 18

3 types of fungi based on nutrition

Answer 18

1. Saprotrophs
2. Parasites
3. Symbionts

Question 19

Saprotrophs

Answer 19

(decomposers) break down dead organic material

Question 20

Parasites

Answer 20

Derive nutrients from living roots

Question 21

Symbionts

Answer 21

(eg. mycorrhizae) form mutualistic relationships with plants

Question 22

Yeast forms reproduction

Answer 22

Asexual - budding / fission

Sexual - mating between one of each mating type

Question 23

Sporulation

Answer 23

Occurs when nutrient resources are depleated

Dispersal and dormant survival

Sizes, shapes, development pathways can be very diverse

Question 24

Many ascomycetes are dimporhic

Answer 24

Hyphal or yeast form / response to envionrmet / no common environmental cue / involves spitzenkorper - repsonse to several systems

Question 25

Fungi propagation and how they disseminate (2)

Answer 25

Asexual - fragmentation, budding or producing spores

Sexual - introduces genetic variation / produces spores / in response to adverse environmental conditions

Question 26

Asexual - spore formation

Answer 26

Fungi produce vast numbers of spores as part of their asexual reproduction. These spores are typically dispersed by wind, water, or animals

Question 27

Asexual - budding

Answer 27

In yeasts (e.g., Saccharomyces cerevisiae), new individuals are formed from the parent by budding

Question 28

Asexual - fragmentation

Answer 28

Some fungi can fragment their mycelium, and each fragment can grow into a new organism

Question 29

Sexual - plasmogamy

Answer 29

Fusion of cytoplasm from two compatible mating types

Question 30

Sexual - karyogamy

Answer 30

Fusion of the nuclei to form a zygote (the diploid stage)

Question 31

Sexual - spore formation

Answer 31

After fertilization, fungi often form specialized reproductive structures that produce spores

Question 32

Symbiosis and Vegetative Propagation - Mycorrhizal Associations

Answer 32

Fungi form symbiotic relationships with plant roots, exchanging nutrients for sugars. Fungi reproduce via spores that colonize new plant roots

Question 33

Symbiosis and Vegetative Propagation - Lichens

Answer 33

Symbiotic associations between fungi and photosynthetic organisms (e.g., algae or cyanobacteria). Lichens reproduce both sexually and asexually by spore release and fragmentation

Question 34

Vegetative Propagation - Yeast

Answer 34

Yeasts reproduce asexually via budding; fragments of the mycelium can also develop into new individuals