Fungi

Question 1

What are the distinct cellular characteristics of fungi?

Answer 1

• Cell wall made of chitin
• No chloroplast

Question 2

How do fungi receive nutrients?

Answer 2

They are heterotrophs, being saprophytic or parasitic.

Question 3

What are fungi most related to?

Answer 3

Animals and choanoflagellates, not plants. No where near plants. Based on DNA analysis.

Question 4

What is the origin of fungi?

Answer 4

Single celled flagellated aquatic ancestor. However there is poor early fossil record.
Multicellularity evolved in fungi separately to animals.

Question 5

Describe the structure of fungi.

Answer 5

• Hyphae (growing vegetative cells) are separated into cells, but hyphae of coenocytic (not separated by septate/septums) lack cross walls.
• can be dikaryotic (two nucleus)

Question 6

What specialised structure do parasitic fungi have?

Answer 6

Haustoria, which penetrates the tissues of a host and absorbs nutrients and water

Question 7

Describe the asexual life cycle of fungi.

Answer 7

Mycelium (n) grows into spore producing structures, then into spores. Then they germinate back into mycelium.

Question 8

What is plasmogamy?

Answer 8

Fusion of cytoplasm in fungi.

Question 9

What is karyogamy?

Answer 9

Fusion of nuclei in fungi, occurs after plasmogamy.

Question 10

Describe the sexual life cycle of fungi.

Answer 10

• Mycelium (n) goes through plasmogamy, moving to a dikaryotic stage (n+n).
• Their nuclei then fuse, moving to a diploid stage.
• Meiosis occurs and spore producing structures are formed. They produce haploid spores.
• They germinate and grow into new mycelium.

Question 11

What do fungi need to germinate?

Answer 11

• Moistness
• Appropriate substrate with stability and nutrients

Question 12

Give a summary of Chytridiomycota.

Answer 12

• Flagella in zoospores
• Single celled or coenocytic.
• Causing a global extinction wave of amphibians, causing 100% mortality after infection.

Question 13

Give a summary of Zygomycota.

Answer 13

• Dikaryotic zygosporangia
• Feed on soil or decaying material (bread)
• Hyphae are coenocytic
• Septae in reproductive hyphae
• Fastest acceleration of any organism (2x faster than a bullet)

Question 14

Give a summary of Glomeromycota.

Answer 14

• Symbiotic relationship with plants, having arbuscular mycorrhizae.

Question 15

Give a summary of Ascomycota.

Answer 15

-65,000 species
- Septate hyphae
- Ascospores (8 of them) in asci (spore producing organ)
- Reproduce asexually via conidia

Question 16

Give a summary of Basidiomycota.

Answer 16

• 30,000 species
• Known as club fungi (include puffballs)
• Septate hyphae
• Basidiospores on basidium

Question 17

What are Mycorrhizae?

Answer 17

• Association between plants and fungi.
• Plants benefit from increased surface area + minerals from soil
• Fungi benefit from carbohydrates

Question 18

What are yeasts?

Answer 18

Not a taxonomic group.
- Growth form found in Ascomycota and Basidiomycota
- Single celled but evolved from multicellular ancestor.
- Reproduce via budding asexually or sexually via spores.

Question 19

What % of fungi are parasitic?

Answer 19

30%.

Question 20

What are Microsporidia?

Answer 20

• Highly specialised
• Not part of five phyla
• Intracellular parasites impacting many animals

Question 21

What are lichens?

Answer 21

• Symbiotic association between green algae and fungi
• Evolved multiple times
• Algae/bacteria give nutrients, fungus gives an environment
• Reproduce via fragments and soredia

Question 22

What particular algae, bacteria and fungi are lichens?

Answer 22

• Photobiont algae/bacteria
• Ascomycete/basidiomycete fungi