Fungi I

Flashcards covering the classification, life cycles, anatomy, and ecological roles of fungi as presented in the BIOL2038 and BIOL2044 lecture.

What are the common features shared by organisms in the Kingdom Fungi?

No chlorophyll and no photosynthesis, heterotrophic (secrete degrading enzymes and use ready-made nutrients), cell walls consist of chitin and they are non-vascular, mostly as multi-cellular hyphae and can have spores

What are the main groups of fungi

Mushrooms, yeasts and moulds

What is the difference between a hypha and a mycelium?

A hypha is a filament of cells (which can be septate or coenocytic), while a mycelium is a mass of hyphae.

What is a conidiophore

A conidiophore is a specialized hyphal structure that produces conidia, which are asexual spores in fungi. It plays an important role in fungal reproduction. Appears on aerial hyphae

What is a sporangiophore

A sporangiophore is a specialized hyphal structure (stalk) that bears sporangia, which are spore containers in fungi. It is involved in the asexual reproduction of certain fungi.

What is the fruiting body of a fungus

aerial spore bearing reproductive structure

What is a spore

A reproductive structure that can develop into a new organism, often used for asexual reproduction in fungi. They are often pigmented.

What spore types are there

Chlamydospore, conidiospores, zygospores, ascospores and basidiospore

What is a Chlamydospore?

A thick-walled spore formed by the thickening of hyphal cells, usually resistant to desiccation and unfavourable conditions. They are asexual spores

What is a conidiospore

An asexual spore formed at the tips of hyphae, typically released into the air for dispersal. Conidiospores can be found in various shapes and sizes. (conidiophore)

What is a zygospore

A diploid spore, arising in zygosporangium upon fusion of hyphae and germinate into a sporangium. Zygospores can remain dormant until favourable conditions arise. They are diploids

What is an ascospore

A type of sexual spore formed within an ascus, resulting from the fusion of two compatible nuclei. Ascospores are typically released when the ascus matures and can vary in number and shape.

What is a basidiospore

A type of sexual spore produced by basidiomycetes, formed on a basidium after the fusion of nuclei. Basidiospores are commonly released into the environment for dispersal.

What are the stages of the lifecycle of a fungus

Haploid stage, plasmogamy, Dikaryotic stage (heterokaryotic), Karyogamy, meiosis, spore formation, germination and asexual reproduction

What occurs in the haploid stage of the lifecycle of a fungus

All fungi start as haploid spores with one copy of their genetic information. The spore will germinate and produce a mass of ‘roots‘ called a mycelium after it lands in a favourable environment. These roots provide nutrition to the spores, allowing them to grow

What occurs in the plasmogamy process in the lifecycle of a fungus

Plasmogamy is where the cytoplasm of two mating fungal cells merge. This fusion allows the two parent cells to combine resources. Following this, is the dikaryotic stage.

What occurs in the dikaryotic stage of the lifecycle of a fungus

In the dikaryotic stage, two genetically distinct nuclei coexist within the same cell, following the fusion of mycelia from different mating types. This stage can persist for extended periods until conditions are suitable for sexual reproduction, leading to the formation of fruiting bodies.

What occurs in the karyogamy process in the lifecycle of a fungus

This is the fusion of the two nuclei within the daughter cell that has been formed due to the favourable environmental conditions. The resulting diploid cell can then undergo meiosis, creating genetically diverse spores.

What occurs in the spore formation process in the lifecycle of a fungus

In spore formation, the diploid cell undergoes meiosis to produce haploid spores, which can disperse and germinate under favourable conditions, leading to new fungal individuals. This process ensures genetic diversity and adaptation.

What occurs in the germination process in the lifecycle of a fungus

During germination, a spore absorbs water and nutrients, activating metabolic processes that lead to its growth into a new mycelium. This process marks the transition from a dormant spore to an active fungal organism.

What occurs during the asexual reproduction of fungi

Conidia spores are formed externally on specialised structures known as conidiophores. This production allows fungi to quickly adapt to environmental changes by generating numerous offspring that can disperse widely.

What occurs during the asexual reproduction of fungi like yeasts

A new cell forms as an outgrowth of the parent cell, eventually detaching to lead an independent existence. This method is efficient for unicellular fungi, enabling then to rapidly exploit available resources.

What happens in fragmentation asexual reproduction of fungi

Mycelium breaks into smaller pieces, each capable of growing into a new organism.

What are the characteristics of Zygomycota?

They typically include moulds, featuring coenocytic hyphae (except in reproductive hyphae) and dikaryotic zygosporangia.

Why is Basidiomycota referred to as 'club fungi'?

Because their spore-bearing structure, the basidium, looks like a club.

How many spores are typically found on a basidium compared to an ascus?

There are typically 4 basidiospores on a basidium, while an ascus usually contains 8 ascospores (though many yeast have 4).

What are the characteristics of Ascomycota

Ascomycota, also known as sac fungi, are characterized by the production of ascospores in a sac-like structure called the ascus, and they often feature septate hyphae. They often have 8 ascospores in an ascus

Are yeast considered a distinct taxonomic group?

No, they are not a distinct taxonomic group but are defined by their single-celled growth and belong to either Ascomycota or Basidiomycota.

What is the most familiar species of yeast used in baking and brewing?

Saccharomyces cerevisiae.

What role do fungi play as primary decomposers of litter?

They break down dead material, including lignin, by excreting enzymes and absorbing nutrients, which makes those nutrients available to other organisms through recycling.

What is mycorrhiza

A symbiotic association between fungus and the roots of a vascular plant

What is ectomycorrhiza

Extracellular and the fungus relies on carbohydrates ‘leaking‘ from plant root cells. They can happen in 2% of all plant species

What is endomycorrhiza

A type of mycorrhiza where the fungus invades the root cells of the plant, forming structures called arbuscules and vesicles. The fungus has a specialised structure called haustorium which penetrates the plant root cell wall. It can happen in 70% of all plant species

What is a lichen?

A mutualistic symbiosis between fungi and either green algae or cyanobacteria.

What is the difference between an opportunistic and an obligate fungal pathogen?

An opportunistic pathogen is normally not parasitic but exploits conditions like an immunocompromised host, while an obligate pathogen cannot survive without the host.

Provide three examples of fungal pathogens and the hosts they affect.

Rust fungus affects plants, White-nose syndrome affects bats, and Chytridiomycosis affects amphibians.