Chapter 31 Flashcards
(41 cards)
Describe the structure of fungi known as mycelia
Mycelia are vast networks of filaments underground that link hundred of meters apart
What is the function of spores in fungi
Spores enable fungi to colonize new environments by germinating and growing when conditions are favorable
Define the role of decomposers
Decomposers are fungi that break down and absorb nutrients from nonliving material in ecosystems
How do fungi derive nutrition
Fungi are heterotrophs that feed by absorbtion of nutrients from outside their bodies, using hydrolytic enzymes to break down complex molecules
Describe the body structure of fungi
Fungi can have multicellular filaments, single celled(yeasts) or both with hyphae having tubular walls strengthened with chitin
what is the significance of mycelium in fungi
mycelium is an interwoven mass of hyphae that infiltrates the food source maximizing surface to volume ratio for efficient absorption
describe the structure and function of arbuscules in mycorrhizal fungi
arbuscules are specialized hyphae that penetrate plant cell walls to facilitate nutrient exchange between fungi and plants
what are the two main types of mycorrhizal fungi and how do they differ in their root colonization strategies
Ectomycorrhizal fungi form sheaths of hyphae over the root surface, while arbuscular mycorrhizal fungi extend arbuscules through the root cell wall.
Explain the process of plasmogamy in fungi.
Plasmogamy is the union of cytoplasm from two parent mycelia, leading to the formation of a heterokaryon or a dikaryotic mycelium.
How do fungi reproduce sexually, and what role do pheromones play in this process?
Fungi reproduce sexually by the fusion of hyphae from different mating types, facilitated by sexual signaling molecules called pheromones.
Discuss the evolutionary relationship between fungi, animals, and plants based on their ancestry.
Fungi and animals are more closely related to each other than either group is to plants, with their ancestry traced back to an aquatic, single-celled, flagellated protist.
What evidence supports the early colonization of land by fungi and their mutualistic relationships with early plants?
Fossil evidence and molecular analysis indicate that fungi were among the earliest colonizers of land, forming mutualistic relationships with early plants.
Describe the characteristics and habitats of cryptomycetes and microsporidians, two basal fungal lineages.
Cryptomycetes are unicellular, flagellated spore-forming fungi found globally in various habitats, while microsporidians are unicellular parasites of protists and animals, including humans.
Describe the characteristics of Nosema cere.
Nose ceranae is a parasite of honeybees with a chitin-rich cell wall, highly reduced mitochondria, small genomes, and spores that infect host cells via harpoon-like organelle.
What are some key features of Chytrids?
Chytrids are fungi with about 1000 species found in various habitats, including lakes and soil. They have flagellated spores, chitin cell walls, and can function as decomposers, parasites, or mutualists.
How do Zoopagomycetes reproduce?
Zoopagomycetes form filamentous hyphae and reproduce asexually via non-flagellated spores. Some species induce behavioral changes in the insects they parasitize.
Define Mucoromycetes and provide an example.
Mucoromycetes are fungi with about 750 species, including important decomposers like Rhizopus stolonifer, responsible for breaking down bread. They can live as parasites, pathogens, or mutualists with plants.
Describe the life cycle of Rhizopus stolonifer.
Rhizopus stolonifer, a typical Mucoromycete, spreads coenocytic hyphae to absorb nutrients, produces sporangia asexually, forms zygosporangia for sexual reproduction, and releases genetically diverse haploid spores.
What are some characteristics of Ascomycetes?
Ascomycetes, with about 90,000 species, vary from unicellular yeasts to complex cup fungi. They are called sac fungi due to their asci, produce ascocarps during the sexual stage, and form symbiotic associations like lichens and mycorrhizae.
Describe the reproduction process of Neurospora crassa.
Neurospora crassa reproduces asexually by producing enormous numbers of asexual spores called conidia at the tips of specialized hyphae called conidiophores.
What is the significance of the basidium in basidiomycetes?
The basidium is a cell in which karyogamy and meiosis occur in basidiomycetes, leading to the production of spores for reproduction.
How do basidiomycetes contribute to the decomposition of wood?
Basidiomycetes are important decomposers of wood, with certain species being particularly adept at decomposing lignin, a complex polymer abundant in wood.
Define mycorrhizae and give an example of basidiomycetes that form mutualistic relationships involving mycorrhizae.
Mycorrhizae are symbiotic associations between fungi and plant roots. An example of basidiomycetes forming mycorrhizal relationships is seen in certain mutualistic species within this fungal group.
Define mycorrhizae and give an example of basidiomycetes that form mutualistic relationships involving mycorrhizae.
Mycorrhizae are symbiotic associations between fungi and plant roots. An example of basidiomycetes forming mycorrhizal relationships is seen in certain mutualistic species within this fungal group.
