Bio 151 Exam 2 NKU Questions And Answers

General features of fungi - ANS -Heterotrophic -polysaccharide cell walls with chitin -external digestion -hyphae -some are unicellular (yeast) Hyphae - ANS each of the branching filaments that make up the mycelium of a fungus. Mycelium - ANS mass of hyphae Chytridiomycota - ANS -aquatic, flagellated fungi -sexual gametes and asexual spores are motile fungal asexual reproduction - ANS spores are formed through budding or mitosis; conidia or sporangiospores fungal sexual reproduction - ANS Way that fungi reproduce which involves four different stages: haploid hyphae, dikaryotic stage, diploid zygote, spores Zygomycota - ANS -bread molds -asexual reproduction most common via sporangium -sexual reproduction - zygosporangium Ascomycota - ANS -sac fungi -Asexual reproduction - via conidium -Sexual reproduction spores via ascus found on ascocarp -dikaryotic - two nuclei Basidiomycota - ANS club fungi -named for sexual reproductive structure, basidium, found on basidiocarp -asexual reproduction is rare Lichens - ANS represent symbiotic relationships between a fungus and a photosynthetic partner Mycorrhizae - ANS -A mutualistic association of plant roots and -fungus Increased absorption Photosynthetic products leaf cutter ants - ANS cultivate underground fungal "gardens" that grow on cut leaves to feed as food to the ant larvae in the nest endophyte - ANS A fungus that lives inside a leaf or other plant part without causing harm to the plant. -protection from herbivores via fungal chemicals Ecology of Fungi - ANS -Mutualistic associations -Pathogens -Important decomposers -Most decomposition of wood -Economic uses Desication - ANS Drying out due to the evaporation of water Anatomy of a Vascular Plant - ANS Shoot: -reproductive organs -leaf -stem Roots leaf - ANS The major sites of photosynthesis in most plants. Stomata - ANS Small openings in the surface of the leaf that allow for gas exchange (e.g. H2O, CO2); flanked by guard cells open stomata - ANS Allow CO2 to diffuse from the air into photosynthetic tissues Allow O2 to diffuse out of these tissues into the air Uptake of solutes by guard cells causes water to be drawn in by osmosis. As the guard cells swell, they bow apart, opening the stoma closed stomata - ANS Conserve water on hot, dry days -Release of solutes causes water to flow out of the guard cells, closing the stoma facilitated diffusion - ANS K+ (& Cl-) move into guard cells by facilitated (active) transport -H+ leaves the cell in-order for K+ and Cl- to enter. abscisic acid - ANS -initiates closing of stomata -Stomata will also close due to prolonged dehydration -ABA binds to a receptor and kicks out potassium and chloride to close the stomata. Xylem - ANS vascular tissue that carries water upward from the roots to every part of a plant Transpiration - ANS "pulls" water through stomata - unidirectional Phloem - ANS The vascular tissue through which food moves in some plants Translocation - ANS bidirectional,distribution of carbohydrates throughout the plant Adhesion - ANS water observed to stick to sides of xylem elements Cohesion - ANS water has inherent tensile strength that varies inversely with the diameter of the column tension - ANS negative pressure driving force generating tension is transpiration adhesion-cohesion theory - ANS Evaporation from leaves (transpiration) -water pressure gradient on entire water column (xylem) to the roots "Pulls" water from soil to roots to leaves to atmosphere root endodermis - ANS functions as a molecular filter that allows the passage of beneficial solutes that have entered from the symplast or have been specifically transported into endodermal cytosol through specific transport channels root presure - ANS - movement of water up the xylem column despite absence of transpiration Active transport High root pressure may lead to guttation nitrogen-fixing bacteria - ANS Transform N2 into forms that can be utilized by plants and other organisms Mass flow hypothesis - ANS dissolved carbohydrates flow from a source and are released at a sink Photorespiration - ANS O2 is incorporated into RuBP rather than CO2 - decreased yields of photosynthesis Occurs when O2 builds up and CO2 declines - e.g. prolonged closing of stomata CAM plants - ANS plants close their stomata during the day, collect CO2 at night, and store the CO2 in the form of acids until it is needed during the day for photosynthesis C4 plants - ANS A plant that prefaces the Calvin cycle with reactions that incorporate CO2 into four-carbon compounds, the end product of which supplies CO2 for the Calvin cycle.