LEARNING OBJECTIVES FOR BIOLOGY 241

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1 LEARNING OBJECTIVES FOR BIOLOGY 241 This document outlines the learning objectives (what students will know, understand or be able to do) after completing Biology 241. For some learning objectives, explicit learning outcomes have been provided as well; these outcomes are specific, measureable learning goals that illustrate one way in which students should be able to demonstrate their knowledge. I. LECTURE COMPONENT: CONSISTS OF FOUR THEMES: THEME 1: THERMODYNAMICS AND LIFE THEME 2: ENERGY TRANSFORMATIONS IN ORGANISMS THEME 3: COST OF LIVING: ENERGY ALLOCATION IN ORGANISMS THEME 4: ENERGY FLOW AND NUTRIENT CYCLING IN ECOSYSTEMS THEME 1: THERMODYNAMICS AND LIFE A. Organisms convert energy into a form that can be used in cellular processes B. What happens to energy when it is transformed? C. Spontaneous reactions & Gibbs free energy D. Energy & metabolic pathways Learning Objectives for Theme 1 Topics A, B & C 1. Define energy; differentiate between kinetic/potential energy and provide examples of each in biological systems. a) Given a list of types of energy, categorize these as kinetic or potential energy. b) Explain why chemical bonds and electrons are important forms of potential energy in cells. 2. State the First and Second Laws of Thermodynamics and explain how they apply to biological systems. a) Apply the Laws of Thermodynamics to specific cellular processes and explain how the Laws are evident in that process. b) Given a scenario involving a reaction and a description of the fates of the energy released, assess whether the scenario violates the First Law. c) Defend the concept that living organisms do not violate the Second Law of Thermodynamics 3. Define enthalpy (H), entropy (S) and free energy (G) and explain the relationship among these parameters. 4. Differentiate between endergonic and exergonic reactions and relate the free-energy change to the spontaneity of a reaction. Explain the relationship between the magnitude of ΔG for a reaction and the energy yield or requirement for that reaction. a) Given the ΔG value for a reaction, indicate whether that reaction is exergonic or endergonic. b) Draw and interpret diagrams showing free energy changes for exergonic and endergonic reactions c) Correctly use the term spontaneous in reference to a reaction. 1

2 d) Provide an example of an important biochemical reaction in the cell with a negative ΔG value and one with a positive ΔG value. Learning Objectives for Theme 1 Topic D Energy & Metabolic Pathways: 1. Differentiate between catabolic and anabolic pathways in terms of overall ΔG. a) Differentiate between the overall ΔG of the pathway and the ΔG of individual steps in the pathway, e.g., explain why each step in an energy-yielding pathway is not necessarily exergonic. 2. Compare and contrast equilibrium and metabolic homeostasis and explain why the latter occurs in cells and organisms. 3. Relate protein function to three-dimensional shape (conformation) and describe the four levels of structure that contribute to its shape. a) Predict the effect of denaturation on protein function. 4. Explain how enzymes alter a reaction rate by reducing the activation energy required for a reaction by stabilizing transition states a) Draw a diagram illustrating the induced-fit model of enzyme activity. b) Explain the role of the active site in forming the transition state and the properties of the active site that allow it to play this role 5. Explain why ATP is said to be the primary energy currency of all cells and its role in driving endergonic reactions in cells. a) Draw a simple diagram showing the structure of ATP and use that diagram to explain why ATP hydrolysis and the phosphoryl group-transfer reactions of ATP are exergonic. b) Draw a simple diagram to illustrate how proteins such as enzymes function as energycoupling agents, and explain the role of ATP in such coupled (connected) reactions. THEME 2: ENERGY TRANSFORMATIONS IN ORGANISMS A. Energy & C sources for organisms 1. Classification of organisms 2. How do chemical sources of C/energy enter cells? B. How do chemotrophs transform the potential energy in reduced molecules into ATP? C. How do phototrophs transform light energy into chemical energy? Learning Objectives Theme 2 A Energy & C sources for organisms 1. List and describe the three Domains of life and explain the reason why this classification system has replaced the older five Kingdom system. 2. Compare and contrast prokaryotic and eukaryotic cells; explain the importance of organelles to the functioning of eukaryotic cells. 2

3 3. Compare and contrast the energy and carbon sources for chemolithotrophs, chemoorganotrophs, photoautotrophs and photoheterotrophs. 4. Define lipid and explain how lipids differ from other biomolecules. Describe the lipids that compose membrane bilayers and explain how their properties relate to structure. 5. Explain how the structure of phospholipids allows them to form membranes and why phospholipids confer selective permeability on membranes. 6. Describe membrane structure according to the fluid mosaic model of membrane structure and explain the roles of proteins and sterols in membrane function. 7. Compare and contrast carrier proteins and channel proteins. 8. Compare and contrast passive diffusion, facilitated diffusion and active transport in terms of: which types of transport involve integral proteins, which require input of cellular energy, and the type of molecules that move by each means. 9. Compare and contrast primary and secondary active transport. Learning Objectives Theme 2 B How do chemotrophs transform the potential energy in reduced molecules into ATP? 1. Explain how energy is released when electrons are transferred in redox reactions; given a reaction, identify which molecules are oxidized and which are reduced. 2. Explain the role of glycolysis in energy transformation as well as production of intermediates for further metabolic reactions 3. Compare and contrast irreversible and reversible inhibition, and competitive and noncompetitive inhibition of enzymes. 4. Explain how regulatory enzymes differ from other enzymes, and how/why cells control activity of these enzymes via allosteric regulation, and explain why feedback inhibition is a common example of this type of regulation. 5. Explain why glucose is an important source of energy and why it is oxidized in a series of reactions, rather than all at once. 6. Describe the conserved pathways/mechanisms for transforming/using energy within a cell/organism (ATP/reducing power/gradients). 7. Describe the different types of chemical energy used by the cell to perform work (e.g. ATP, proton motive force, NADH/NADPH/FADH 2 ) and explain the role of electron carrier molecules in metabolic pathways. 8. Describe the three pathways by which glucose is oxidized in aerobic respiration (glycolysis; Krebs cycle; electron transport chain & chemiosmosis) and be able to diagram the relationship among these four pathways. For each pathways, students do not need to memorize all of the reactions but they do need to know: what are the starting molecules for this process? what molecules are produced? how is ATP synthesized in this step? (i.e. by what process?) 3

4 what is the main accomplishment of the pathway? where is most of the energy that was originally present in glucose at the end of this process? where in eukaryotic and prokaryotic cells does this pathway occur? how is the pathway similar in eukaryotic and prokaryotic cells and how is it different? 9. Explain how glycolysis produces metabolic energy as well as producing intermediates for further metabolic reactions. 10. Explain how pyruvate oxidation allows for aerobic respiration to proceed in the presence of oxygen. 11. Describe the process of chemiosmosis: Explain how electrons flow along the series of membrane-bound complexes that make up the electron transport chain (ETC) Describe and be able to diagram how the flow of electrons along the ETC creates a proton motive force Describe and be able to diagram how the proton motive force is used to produce ATP via ATP synthase Explain why oxygen is required for aerobic respiration 12. Given a scenario involving blockage or breakdown of electron flow along the ETC, be able to predict the effect on the overall process of respiration. 13. Explain the benefit obtained by organisms that can use aerobic respiration in terms of overall ATP production per unit of glucose. 14. List and explain the evidence for the endosymbiotic evolution of mitochondria. Describe the similarities and differences in structure between a prokaryotic cell and mitochondrion. 15. Diagram and explain the events required for a prokaryotic cell to evolve into an organelle. 16. Describe an example of a modern endosymbiosis. 17. For fermentation, anaerobic respiration and chemolithotrophy, students do not need to memorize all of the reactions but they do need to be able to: Describe and be able to diagram one example of each pathway (what are the starting molecules for the process; what molecules are produced; by what process is ATP made in this process?) Explain the importance of the pathways to humans Explain whether the process occurs in both eukaryotic and prokaryotic cells and where in each type of cell it occurs Compare and contrast the efficiency of ATP production by each of these pathways to that of aerobic respiration, and explain why the efficiencies differ using a table of redox potentials. 18. Explain how fermentation allows glycolysis to continue in the absence of oxygen and describe common features shared by all fermentation pathways. 19. Define biofilm formation (in the context of chemolithotrophic organisms) and discuss the advantages of growth within a biofilm to prokaryotic organisms. 4

5 Learning Objectives Theme 2C How do phototrophs transform light energy into chemical energy? 1. Compare and contrast oxygenic and non-oxygenic photosynthesis. 2. Interpret data from experiments on the source of oxygen produced during oxygenic photosynthesis. 3. Draw chloroplast structure and indicate the locations of the light-independent and -dependent reactions. 4. Draw a diagram outlining the major steps in the flow of energy through photosynthesis, from sunlight to carbohydrate. 5.Explain how the overall organization of photosystems allows solar energy to be captured and initiate electron transport within the chloroplasts. Explain how accessory pigments are important in this process. 6. Outline how energy flows between the light-dependent and -independent reactions of photosynthesis. 7. Draw how electron flow through the photosynthetic electron transport chain results in the formation of a proton motive force and synthesis of ATP. 8. Describe the basic differences between non-cyclic and cyclic electron flow, and how cyclic electron transport helps to balance ATP and NADPH ratios. 9. Compare/contrast chemiosmosis in respiration and in photosynthesis (i.e., how is oxidative phosphorylation similar to/different from photosynthetic phosphorylation?). Be able to draw a figure comparing these two processes. 10. Draw the three major stages of the carbon-fixation reactions, and the basic outcome of each 11. Explain why the carbon fixation reactions are referred to as a cycle (the Calvin-Benson cycle) and why the cycle needs to turn more than once to produce carbohydrate. 12. Compare and contrast, using labeled diagrams, the location of photosynthetic pigments in cyanobacteria and eukaryotic cells. 5

6 THEME 3: COST OF LIVING Topic A: Energy Allocation Topic B: Homeostasis Topic C: Locomotion Topic D: Reproduction Learning Objectives Theme 3A Energy Allocation 1. Explain what the principle of allocation; use known characteristics of an organism s life history to predict how energy is allocated among competing functions. 2. Provide examples of tradeoffs that organisms make in energy allocation. 3. Compare how energy is allocated towards different functions in cells as well as in different organisms (i.e., compare/contrast the energy budgets of different cells/organisms). 4. Describe why minimal (resting or standard) metabolism is a non-negotiable component of an organism s energy allocation. 7. Explain the relationship between metabolic rate and body size; be able to graph both metabolic rate and mass-specific metabolic rate and explain why the relationship between the two factors is different in the two graphs. Describe the importance of mass-specific metabolic rate in comparisons between organisms. 5. Explain why metabolic rate can be used to measure energy use by an organism, and why changes in O 2 evolution or CO 2 consumption can be used to determine metabolic rate in many organisms. 6. Calculate energy budget components; be able to interpret results to assess the impact of changes in energy budgets on biomass. 7. Describe the importance of mass-specific metabolic rate in comparisons between organisms Learning Objectives Theme 3B Homeostasis 1. Define homeostasis; compare and contrast negative and positive feedback, and explain which type of feedback is most important for maintaining homeostasis and why. 2. Describe how metabolic energy is used to maintain homeostasis, using temperature regulation as an example. 3. Differentiate between ectothermy and endothermy and between heterothermic and homeothermic temperature regulation strategies. 4. Draw and interpret graphs showing metabolic rate over a range of temperatures for both endotherms and ectotherms. 5. Describe the processes by which an organisms exchanges heat with its environment and explain mechanisms by which an organism can regulate heat exchange. 6. Explain the role of torpor in energy conservation; differentiate between torpor and hibernation. Explain how metabolic energy is used during hibernation to generate body heat and how it is different/similar to normal heat production in endotherms. 6

7 6. Describe how metabolic energy is used to maintain homeostasis, using regulation of water balance as an example. 7. Describe how solutes influence the movement of water across a semipermeable membrane. 8. Explain the role of compatible solutes in allowing extreme halophilic organisms (e.g., Halobacterium) to survive in environments with high concentrations of salts. Learning Objectives Theme 3C Energy & Locomotion 1. Relate energy costs for movement to pathways for ATP synthesis in animals; explain the roles of glycolysis and oxidative phosphorylation in meeting energy demands when an animal begins to move. 2. Explain why movement is the primary energy cost above minimal metabolism for many organisms, e.g. needed to find prey or avoid predation; to locate food or other resources. 3. Explain the costs of movement for an organism; given data or graph, interpret data in terms of costs/benefits of movement and tradeoffs between movement and other uses of energy. 4. Compare and contrast the relative costs of various types of movement in animals (i.e. terrestrial locomotion vs. flying vs. swimming), and explain why some forms of locomotion involve greater costs. 5. Relate costs of movement in different environments (e.g.. terrestrial vs. aquatic) to body size. Learning Objectives Theme 3D Energy and Reproduction 1. Explain why energy is needed for growth (e.g. to drive anabolic pathways; synthesis of new tissues), repair/maintenance and for reproduction (e.g. production of gametes, spores; support of offspring). 2. Define life history ; explain how and why life history strategies vary among species/populations. 3. Be able to interpret life tables and survivorship curves; describe the three types of survivorship curves and provide an example of an organism exhibiting each type of curve. 4. Explain what is meant by a life-history tradeoff; given data or graph, interpret data in terms of costs/benefits and tradeoffs between reproduction and other uses of energy. 7

8 THEME 4. ENERGY AND ECOSYSTEMS Topic A: Growth of populations Topic B: Energy flow in ecosystems Topic C: Nutrient cycling Learning Objectives for Theme 4 Topics A & B: 1. Explain the difference between exponential and logistic models of population growth (e.g., what type of population growth does each model describe? 2. Define the terms in the equation for exponential population growth; given data, be able to use the equation. 3. Explain what different values of r indicate about population growth (e.g., what does it mean when r=0?) 4. Define r max and explain under what conditions it would occur. 5. Define carrying capacity. 6. Differentiate between density-dependent and density-independent factors and explain how each influences population growth. 7. Compare and contrast r- and K-selected species 8. Define ecosystem and describe the components of an ecosystem (abiotic environment, primary producers, consumers, etc.). 9. Apply the Laws of Thermodynamics to energy transformations at the level of ecosystems i.e. explain how energy is transformed in ecosystems, how it flows through an ecosystem and why continual input of energy is required for ecosystem function. 10. Explain why nutrients, unlike energy, are recycled in ecosystems. 11. Define primary production; differentiate between net and gross primary production. Explain why most ecosystems are based upon phototrophs, but some have chemosynthesis as their foundation. 12. Describe the factors that influence rates of primary production. 13. Define and differentiate between: secondary production, net production efficiency, and ecological efficiencies. Given data from an ecosystem, be able to calculate these parameters. 14. Explain why ecological efficiencies are so low (i.e. explain how energy flows from one trophic level to another in a food chain or food web and why energy is lost at each step). 15. Compare and contrast top-down and bottom-up regulation of ecosystems. 8

9 Learning Objectives for Theme 4 Topic C Nutrient cycling 1. Define biogeochemical cycle. 2. Describe the compartments (reservoirs) in which nutrients accumulate and explain the processes by which nutrients cycle within and among these compartments; explain how the form(s) that nutrients take influences how they cycle among these compartments. 3. Describe the major compartments through which N cycles and explain the processes by which it cycles; describe the overall path of nitrogen from atmosphere to a form that photoautotrophs can assimilate; explain the role of chemolithotrophic and chemoorganoheterotrophic prokaryotic organisms in these transformations of N. 4. Describe the major compartments through which C cycles and explain the processes by which it cycles. 5. Explain why nutrients and energy move through different ecosystems at different rates, e.g. compare rates of accumulation and breakdown of organic matter among ecosystems. 6. Explain how human activities have influenced energy flow and nutrient cycling in ecosystems and how these changes have altered ecosystem structure and function (e.g., relate ocean acidification to disruptions in the C cycle). II. LABORATORY COMPONENT Upon completion of the laboratories in Biology 241, students should be able to: 1. Explain the concept of the scientific method (i.e., explain how scientists make observations, collect data and draw conclusions). 2. When provided with a question, develop a hypothesis, and design an experiment to test the hypothesis, i.e., identify independent and dependent variables as well as variables to be held constant and an appropriate control. [In Biology 241, students design and conduct experiments in the context of a guided-inquiry approach. In this approach, students learn a procedure (e.g. how to measure enzyme activity using a spectrophotometer) and generate a set of results, which provide a starting point for designing an experiment. Students are then provided with questions from which they develop hypotheses, and work in small groups to design an experiment]. 3. Calculate descriptive statistics (mean and standard error of the mean) and present these descriptive statistics correctly in tables and figures (line and bar graphs). 4. Prepare written Results section of a lab report. 5. Interpret results (i.e., determine whether results support hypothesis) [In Biology 241, interpretation is done by answering a series of questions; in Biology 243, students learn to prepare a Discussion section]. 6. Demonstrate understanding of experimental error. 7. Explain what constitutes plagiarism and explain how and when to put information from a source into own words. 8. Cite sources of information following CSE format in both text and a Literature Cited section. 9

10 9. Describe and explain the parts of a scientific paper; read and interpret sections of a scientific paper [chosen for them]. 10. Interpret figures in which descriptive statistics are presented. 11. Present results of an experiment and/or information from a source of scientific information orally. 12. Use a compound microscope. 13. Use micropipettors, electronic balance and vortex. 14. Calculate dilutions; prepare serial dilutions of a stock solution. 15. Use a spectrophotometer to measure concentration of a pigmented molecule in solution (e.g. to measure enzyme activity). 16. Prepare and use a standard curve. Specific topics currently taught in Biology 241 labs (these will change over time): 1. Design an experiment to investigate the effect of inhibitors on enzyme activity; interpret results to distinguish between competitive and non-competitive inhibitors. 2. Be able to draw and interpret Michaelis-Menten and Lineweaver-Burk plots. 3. Define eutrophication ; explain how this process occurs and its impact on aquatic ecosystems. 4. Develop and test hypotheses relating to the effect of nutrient enrichment on various components of aquatic microcosms (aquatic plants; zoo- and phytoplankton; water chemistry). Collect and summarize data and draw conclusions about hypotheses. 5. Explain the economic and environmental costs and benefits of various types of biofuels. 6. Explain how ethanol is produced via fermentation. 7. Design an experiment to compare the biological efficiency of the fermentation process for corn, sugarcane and wheat. 8. Integrate results with information on the economic/environmental impacts of different biofuels to draw conclusions about the sustainable use of various plants as alternative energy sources. 9. Measure photosynthetic activity using a spectrophotometer. 10. Design and conduct a simple experiment to measure the Hill reaction in isolated chloroplasts. 11. Identify and describe the roles of primary producers, herbivores and predators in a community. 12. Describe and illustrate the concept of a trophic cascade. 13. Describe and illustrate the roles of food web structure and competitive dominance in determining how changes at one level of a food web can affect organisms across several trophic levels. 10