Brooks Biodiversity Unit 2 Exam with Certified Solutions

The Primary role of Fungi Decomposers- they break things down Modes of Nutrition in Fungi Heterotrophs with extracellular digestion Exoenzymes Fungi Release these enzymes outside of the cell wall. Break down complex molecules into smaller organic molecules which can be absorbed. Extracellular Digestion The release of exoenzymes out side of the cell wall, followed by the absorption of nutrients.. Saprobes Fungi that feed on non-living/dead organisms Symbionts Fungus that lives with another living organism (form a symbiotic relationship) Mutualism in Fungi both organisms benefit, neither is harmed. Ex: Lichens - fungi and algae (cyanobacteria)Ex: Mycorrhizae - fungi and plant roots Commensalism One organism benefits, the other is unharmed Parasitism One organism benefits, the other is harmed Examples of Parasitism in Fungi Ex: Fungus as a human parasite (Athelete's Foot) Ex: Fungus as a plant parasite 1. black stem rust on wheat 2. ergots on rye 3. strawberries with botrytis mold 4. pink ear rot of corn Black Stem Rust Parasitic relationship with fungus and plant. Occurs on wheat Ergots Parasitic relationship with fungus and plant that occurs on rye and gives hallucinogenic sensationsBotrytis Mold Parasitic relationship with fungus and plants that occurs on strawberries Fungi Characteristics 1. Heterotrophic 2. Extracellular Digestion 3. Chitin-Based Cell wall 4. Most fungi are made up of filaments called Hyphae Hyphae filaments (long and branching) that make up the structure of a fungus In most fungi, hyphae are the main mode of vegetative growth Hyphae are Septate or Coenocytic Yeast Yeast is a unicellular fungi and do not have/grow hyphae MOST FUNGI ARE MULTICELLULAR, BUT YEAST IS UNICELLULAR Septate You can see the cell separation because the nuclei are confined in and separated by cell walls Think "separate"Coenocytic You cant see the cell separation. It is multinucleated meaning that there are multiple nuclei not separated by a cell wall Thallus/Mycelium collectively refers to a bunch of hyphae that together make up the body of the fungus Hyphae (smallest unit) make up the mycelium (entire fungus body) Haustoria The hyphal tip of a parasitic fungus that penetrates the cell of other organisms (the host)