Soil Biology & Nutrition: Exploring Horizons, Humus, and Symbiotic Bonds, Quizzes of Microbiology

Download Soil Biology & Nutrition: Exploring Horizons, Humus, and Symbiotic Bonds and more Quizzes Microbiology in PDF only on Docsity! TERM 1 What are the most species rich habitats on Earth? DEFINITION 1 Soils are the most species rich habitats on Earth TERM 2 What are the Soil Horizons? DEFINITION 2 O Horizon -- Undecomposed plant matter A Horizon (Surface Soil) -- High Microbial Activity, High organic matter, tilled by farmers, plant roots, dark black in color, B Horizon (SubSoil) -- Less organic matter, less microbial activity, humus leached from topsoil C Horizon (Soil Base) -- Very little organic matter, very little microbial activity, has rocks from underlying rock bed, develops directly from underlying rock bed TERM 3 What is the composition of soil? DEFINITION 3 Inorganic Mineral Matter (40%) Organic Matter (5%) Air & Water (50%) Micro & Macro-organisms (5%) TERM 4 Soil Formation Steps DEFINITION 4 Photosynthetic Microbes grow on surface (lichens, mosses, algae) -- provide organic matter for heterotrophs Microbial Respiration produces CO2 CO2 dissolves in water to form carbonic acid (H2CO3) Rock Dissolution -- allows water to enter the rock Freezing & Thawing causes cracks Plant roots grow in cracks & cause rocks to fragment further Decomposition down to Sand -> Silt -> Clay TERM 5 Humus DEFINITION 5 Organic matter that is not easily degraded helps structure soil into small particles Can be food source for bacteria -- but more difficult to use Absorbs water TERM 6 Soil forms aggregates containing: DEFINITION 6 Inorganic Soil Particles Organic Matter Air Water TERM 7 What can inhibit oxygen diffusion in soil? DEFINITION 7 Soil compaction Water content TERM 8 Where do Anaerobic bacteria grow in soil particle? DEFINITION 8 Anaerobic bacteria grow in the middle of the soil particle (anoxic) They can produce fermentation products that can be diffused to the surface of the particle TERM 9 Where in Horizon A does the majority of microbial Activity occur? DEFINITION 9 Majority of microbial activity in horizon A takes place in the Rhizosphere (area around the roots) TERM 10 Rhizosphere DEFINITION 10 Area around roots, whose chemistry and microbial growth are effected by the root The root exudes nutrients (Rhizodeposition) TERM 21 Symbiosomes are similar to: DEFINITION 21 Similar to Chloroplasts & Mitochondria TERM 22 What happens once bacteria (rhizobia) are released from the infection thread? DEFINITION 22 They are released into the host cell TERM 23 What induces Nitrogen Fixation in Nodules? DEFINITION 23 Bacteria differentiate into Bacteroids TERM 24 Where does nitrogen fixation occur in nodules? DEFINITION 24 Nitrogen fixation occurs in the bacteroid TERM 25 Energy for Nitrogen fixing inside bacteroids comes from? DEFINITION 25 Aerobic Respiration --- O2 is carried to ETC by Leghemoglobin CAC -> ETC -> ATP synthesis The organic acids (malate, succinate, fumarate) the plant provides are fed into the CAC to produce NADH & FADH2 for ETC TERM 26 What enzyme is used in Nitrogen Fixation? DEFINITION 26 Nitrogenase is used in nitrogen fixation TERM 27 Leghemoglobin DEFINITION 27 Produced by Legume Plant Carries O2 for aerobic respiration -- final electron donor (brings it to the ETC) TERM 28 Crown Gall Disease DEFINITION 28 Involves Inter-Domain DNA transfer (bacteria --> plant) Chemical communication is important TERM 29 Bacterium involved in crown gall disease? DEFINITION 29 Agrobacterium Tumefaciens (tume = tumor) TERM 30 What plasmid is used by Agrobacterium Tumefaciens in Crown Gall disease? DEFINITION 30 The Ti Plasmid is used Portion of the plasmid is T-DNA ---- which is responsible for tumor formation TERM 31 What is transferred in Crown Gall disease? DEFINITION 31 T-DNA is transferred T-DNA is responsible for tumor formation TERM 32 Ectomycorrhizae DEFINITION 32 Outside of root, on surface Form sheath around outside Form Hartig Net between epiderm and cortex -- not inside the cells, but between Reaches further than plant roots -- reaches more nutrients allow for nutrient exchange between ectomycorrhizae (between different plants) Allows for greater diversity TERM 33 Mycorrhizae Relationship with plants is example of? DEFINITION 33 Mutualistic Symbiosis Bidirectional Nutrient Exchange Fungi provide: inorganic N & P Plant provides: organic carbon TERM 34 What kind of nutrient exchange occurs with mycorrhizae? DEFINITION 34 Bidirectional Nutrient exchange TERM 35 Microbes in soil are found in _______ DEFINITION 35 Microcolonies