Fungi Flashcards

Flashcards about Fungi

Evolution of Fungi

The evolution of fungi seems to have appeared around 1 billion years ago, with evidence of fungal hyphae in fossilized remains of ancient plants and biochemical evidence.

Kingdom Fungi

Classified as part of the Plantae Kingdom until later in the 20th century, fungi are organized by morphology of sexual organs, presence of septa, and degree of chromosome repetition (ploidy).

Fungi Characteristics

Fungi are heterotrophic, derive energy from organic compounds, have cell walls composed of chitin, produce pigments (including melanin), and store carbohydrates as glycogen.

Cell Structure and Function (Fungi)

Fungi contain a complex cell structure like other eukaryotic cells, including a membrane-bound nucleus, DNA wrapped around histones, mitochondria, and other membranous organelles, but do not contain chloroplasts.

Anatomy of Fungi

Mycelium is a network of hyphae that obtains nutrients and produces a fruiting body, which is mostly underground. Reproductive structure is the fruiting body (mushroom), producing haploid spores involved in fungal reproduction.

Fungal Reproduction

Fungal reproduction can undergo both sexual and asexual reproduction; most produce haploid spores that go through mitosis to form multicellular haploid organisms, and spores are transported via wind or animal.

Asexual Fungal Reproduction

Asexual fungal reproduction includes budding (expanded cytokinesis), fragmentation (fragments of hyphae grow new colonies), and producing spores genetically identical to the parent.

Sexual Fungal Reproduction

Sexual fungal reproduction allows the introduction of genetic variation, typically arising in adverse environmental conditions. Homothallic mycelia are self-fertile, while heterothallic mycelia require two different but compatible mycelia.

Nutrition (Fungi)

Fungi are heterotrophic and must take in organic molecules to generate energy. Exoenzymes are secreted by hyphae to break down large organic molecules in the environment, and smaller molecules are absorbed across the cell membrane by mycelium.

Fungal Nutrition Types

Most obtain nutrients from decaying organic material, making them saprobes, while some are parasitic and derive nutrients from host tissue.

Amanita muscaria (fly agaric)

Amanita muscaria pigments are associated with the cell wall, providing protection against ultraviolet radiation; some pigments are poisonous to humans.

Fungal Habitat

Fungal habitats are moist, slightly acidic, in both dark and light environments, and vary in oxygen requirements.

Decomposers & Recyclers (Fungi)

Fungi are decomposers and recyclers, breaking down organic material to release molecules necessary for life, such as nitrogen and phosphorous.

Mutualistic Relationships (Plant/Fungi)

Plant/fungi mutualistic relationships involve mycorrhizae, present in about 90% of plant species; ectomycorrhizae wrap roots in a sheath of hyphae, and endomycorrhizae grow within roots. Endophytes live within a plant and secrete toxins.

Mycorrhizae

Fungi interact with other organisms to form a mutualistic relationship, with most terrestrial plant roots connecting to form mycorrhizae. This allows the exchange of nutrients and water to benefit both organisms.

Mutualistic Relationships (Lichen)

Lichen is a fungus that lives in a mutualistic relationship with a photosynthetic organism, where neither can live outside of the relationship, and they are very sensitive to air pollution, making them good indicator species.

Fungivores

An animal that unknowingly disperses fungal spores due to diet.

How Humans Benefit from Fungi

Humans benefit from fungi through nutrient cycling in ecosystems, pest control, mycorrhizae relationship to plant growth, and as food for human consumption and medication.