Study guide BIO 311C Exam 3 Chapters 8, 9, 10, 16, 17 (partly), 54 (partly) 1) Differentiate based on examples: potential energy, kinetic energy, anabolism, catabolism POTENTIAL: stored NRG (chem. NRG in foods) KINETIC: NRG in movement (thermal NRG) ANABOLISM: pathways that CONSUME NRG to build larger molecules from simple ones; ex: polymerization and photosynthesis (6CO2 + 6H2O + light glucose + 6O2) CATABOLISM: RELEASE NRG by breaking down complex molecules into simple compounds; ex: CELLULAR RESPIRATION (6oxygen + glucose 6water + NRG) 2) Know the two laws of thermodynamics. 1) total NRG of a system and its surroundings is constant. NRG cannot be created or destroyed. 2). Total entropy of a system and its surroundings always increases for a spontaneous process. (trend toward randomization) 3)Under what conditions would entropy/enthalpy/free energyof a system increase/decrease? (example polymerization reaction, dehydration reaction , hydrolysis etc). 4)What is Gibb’s free energy? 5)Carbon and nitrogen cycles - what is nitrification and ammonification? 6) Energy flow and nutrient cycling in an ecosystem (54.2) NITROGEN CYCLE: 1) nitrogen enters ecosystem through nitrogen fixation (conversion of N2 by bacteria to forms that can be used to make org comp ) 2) AMMONIFICATION decomposes org nitrogen to NH4+ 3) NITRIFICATION NH4+ is converted to NO3- by nitrifying bacteria. 1
4) Under anaerobic conditions, denitrifying bacteria use NO3- in their metabolism instead of O2, releasing N2 in a process known as DENITRIFCATION Figure 54.2 Microorganisms and other detritivores Detritus Primary producers Primary consumers Secondary consumers Tertiary consumers Heat Sun Key Chemical cycling Energy flow Energy enters, flows through and exits an ecosystem Chemical nutirents cycle within an ecosystem 7) Trophic relationship and nutrient cycling model (54.16) 8) Know to determine if a reaction is exergonic/endergonic, spontaneous/non-spontaneous depending on calculated ∆ G values. (Know the formula: ∆ G = ∆ H – T ∆ S) 2 Organic materials available as nutrients Living organisms, detritus Organic materials unavailable as nutrients Coal, oil, peat Inorganic materials available as nutrients Inorganic materials unavailable as nutrients Atmosphere, soil, water Minerals in rocks Formation of sedimentary rock Weathering, erosion Respiration, decomposition, excretion Burning of fossil fuels Fossilization Reservoir a Reservoir b Reservoir c Reservoir d Assimilation, photosynthesis
Neg G=exergonic (spontaneous) Pos G=endergonic (nonspontaneous)
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