BIOL 1030 Lecture Notes - Protist, Lignin, Heterokaryon
7 May 2018
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Lecture 20: Microorganisms 2
Microscopic hyphae strands, mycelium absorbs substrates, spores are the reproducing
structure. !
Fungal structure:
"hyphae - microscopic tubular, highly branched!
"mycelium (mycelia) - an aggregation of hyphae!
Aseptate: multinucleate!
Septat hyphae: cross-walls present, 1 nucleus per cell (monokaryon), 2 nuclei or more
(dikaryotic)!
Fungi are heterotrophic and cannot make their own food; must be pre-synthesized, either by
eating plants, something that ate plants or something dead, but once living organisms.!
-Act as decomposers (saprotrophs), substrates from once living organisms (organic
compound).!
-Parasites (biotrophs): living substrates, can have specialized structures host-provides
nutrients; parasite-steals nutrients.!
-Mutualisms: mycorrhizas, lichens (teamwork)!
-Predation: hyphae adapts to trap and kill prey, soil nematodes trapped in rings. !
Nutrient extraction: no mouth and have rigid cell walls!
-Extracellular digestion: hyphae produce hydrolytic enzymes!
•Produced by rough ER!
•Transport by golgi!
• Hydrolytic enzymes > Substrate acted upon (polymers of glucose become soluble) >
Digestion> Absorption
Bread Mould: Aseptate, zygomycota; substrate, starch in bread.!
-Mycelium produces amylase (hydrolyze starch enzyme)!
-Starch is hydrolyzed by the amylase!
-Glucose is released from the bread!
-Glucose is absorbed and energy is gained.!
wood=xylem (tissue)!
Cell wall - lignin, hard, brown (glucose) and strong and cellulose, white (glucose)!
"cellulase breaks down cellulose, lignin is left behind!
Ex: sulfur shelf, decays wood; removing cellulose (to become more soluble for absorption)!
Glucose is absorbed for use in cellular respiration, new cytoplasm and cell wall material, other
organic compounds.!
Brown rock fungi: leaves behind cellulose taking in lignin!
"Test for degradation of cellulose using an agar medium; digestion of cellulose (with a
tag, releasing a dye, positive result). !
"Fungal reproduction (also green algae) life cycle:!
-A brief 2N state:!
-Asexual state and sexual state are not fully related (not directly connected)!
•Asexual reproduction: a spore germinates into mycelium and develops by mitosis into
spore-producing structures which make spores and then the cycle repeats!
•Sexual reproduction leads from the asexual reproduction, with the fusion of two spores
(positive and negative), going to plasmogamy to heterokaryotic to karogamy to zygote
making spores through meiosis which germinate to make mycelium. !
Plasmogamy: when cytoplasm joins, but their nuclei do not fuse!
Zygotes immediately return to haploid stage (spores).!
Single-celled unicellular eukaryotes (before protista) comprise the majority of organisms!
-Excavata: have a modified feeding groove, with modified mitochondria and flagella!
•They can be heterotrophic and have cell walls (Giardia intestinal, diplomonad parasite!
-Chromalveolata!
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BIOL 1030 Full Course Notes
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Document Summary
Microscopic hyphae strands, mycelium absorbs substrates, spores are the reproducing structure. Fungal structure: hyphae - microscopic tubular, highly branched mycelium (mycelia) - an aggregation of hyphae. Septat hyphae: cross-walls present, 1 nucleus per cell (monokaryon), 2 nuclei or more (dikaryotic) Fungi are heterotrophic and cannot make their own food; must be pre-synthesized, either by eating plants, something that ate plants or something dead, but once living organisms. Act as decomposers (saprotrophs), substrates from once living organisms (organic compound). Parasites (biotrophs): living substrates, can have specialized structures host-provides nutrients; parasite-steals nutrients. Predation: hyphae adapts to trap and kill prey, soil nematodes trapped in rings. Nutrient extraction: no mouth and have rigid cell walls. Extracellular digestion: hyphae produce hydrolytic enzymes: produced by rough er, transport by golgi, hydrolytic enzymes > substrate acted upon (polymers of glucose become soluble) > Bread mould: aseptate, zygomycota; substrate, starch in bread.
