amoebozoa & fungi

key terms + more

spores

haploid cells that can undergo mitosis to form multicellular, haploid individuals

mycorrhizae

symbiotic structures between roots of plant and underground portion of a fungi; allows fungus and plant to exchange nutrients and water

mycology

scientific study of fungi

chitin

gives structural strength to the cell walls of fungi; key component of fungi cell walls

characteristics of amoebozoa: slime molds

• originally classified as fungi

• individuals can come together to form “supercell” with many nuclei

• important role in nutrient recycling

amoeboid motion

• sliding movement initiated by extension of pseudopodia w/ rest of cell following

• requires ATP and coordination of actin and myosin in the cytoplasm

• motion also used in phagocytosis feeding

characteristics of fungi

• unicellular (yeasts)

• multicellular (hypha and mycelium)

hyphae

fungal filament composed of one or more cells, large surface area-volume ration that has a high capacity for nutrient extraction (more efficient than plant roots)

mycelium

mass of fungal hyphae

characteristics of fungi hyphae

• long, narrow filaments with lots of branches

• cells walls typically made of chitin

• most have septa, some are coenocytic

• super thin —> high surface-to-volume ratios

• increases capacity for absorption & increases evaporation of water

septa

cross walls that divide fungal hyphae into separate cells, contain pores that allow materials to be passed between compartments

coenocytic hyphae

hyphae that are formed by large cells containing many nuclei, do not have septa

exoenzyme

• release digestive enzymes into the environment

• break down insoluble compounds, such as the cellulose and lignin of dead wood, into readily absorbable glucose molecules

characteristics of fungi

• heterotrophs

• saprobes

• no locomotion

saprobes (saprohytes)

organisms that derive nutrients from decaying organic matter

fungi reproduction

• mushrooms are the fruiting (reproductive) bodies of multicellular species

• made of dense hyphae

• produce spores

lichen

close association of a fungus with a photosynthetic alga or bacterium that benefits both partners

fungi pathogens

• many species cause plant or fruit tissue decay and rot

• can also cause mycosis in animals and humans

mycosis

fungal infection in humans

mycorrhiza

the fungal partner of a mutualistic association between vascular plant roots and their symbiotic fungi

heterotrophic

require a source of food, ingesting other living or dead organisms

closest extant relatives of animals

choanoflagellates