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Davidson BIO 111 - Unit III Bioenergetics

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Unit III: BioenergeticsBrief Overview Reading: Chapters 2-6Focused Reading: p 28 Most biological…” stop at “Acids, Bases…”p 25-6 " Chemical Reactions…" stop at "Water:…"p 95-99 "Energy conversions…" stop at "Chemical reactions…"Study Questions:Study Questions:Focused reading: p 138-9 "Properties of Light and Pigment" stop at end of page)Study QuestionsStudy QuestionsFocused Reading: p 68-9 "Plastids photosynthesize or store materials" stop at "Other types…"Study Questions:Focused Reading: p 139-40 "Absorption of a photon…" stop at “Light Absorption…”p 140 Fig 8.6Study Questions:Oxygen + Gasoline ---> Carbon Dioxide + WaterCheat SheetStudy Questions:Focused Reading: p 100-102 "ATP: Transferring…" stop at "Enzymes: Biological catalysts"Study Questions:Harvesting Energy and Generating Oxygen:The Light Reactions of Photosynthesis6CO2 + 12H2O + light energy ----> C6H12O6 + 6O2 + 6H2O12H2O + light energy --------> 6O2 + 24e- + 24H+Study Questions:Synthesizing Food: The Calvin-Benson CycleThe complete cycle is outlined in figure 8.17 on page 148.Study Questions:Study Question:Study Questions:1. Why does paraquat kill marijuana? What affect would this have on marijuana’s ability to make G3P?2. If you wanted to design a weed killer what other steps in photosynthesis could be exploited?Question #2 Why Do Vegetarians Eat Tofu?Study Question:Focused Reading: p 635 “Autotrophs…”, stop at "How does…"Focused Reading: p 465-66 "Nitrogen and Sulfur metabolism" stop at"Prokaryotes and their…"N2 + 8H+ + 8e- + 16ATP ----> 2NH3 + H2 + 16ADP + 16PiStudy QuestionsThe Cyanide ScareA Tale of Two GrapesFocused Reading: p 108 "Metabolism and the…" stop at "Enzyme activity is subject…"p 145 Fig 7.1--note relationship between autotrophs and heterotrophsp 43-46 "Carbohydrates…" stop at "Derivative carbohydrates…"C6H12O6 + 6O2 + 6H2O -----> 6CO2 + 12H2O + energy (ATP + Heat)Focused Reading: p 115-16 "Obtaining energy and electrons…" stop at "An overview…"C6H12O6 + 6H2O ------> 24e- + 24H+ + 6CO2Study Questions:Study Questions:Once the glucose is inside the cytoplasm, it can be oxidized for energy.Focused Reading: p 68 "Mitochondria are…" stop at "Plastids photosynthesize…"CH3COOH <------> CH3COO- + H+Study Questions:Study Questions:Study Questions:Focused Reading: p 132-4 "Regulating the energy pathways" to the end.Study Questions:Study Questions:Unit III: BioenergeticsBrief Overview Reading: Chapters 2-6 Certainly one of the primary differences between biological creatures and inanimate objects is their structural organization. Organisms are built from cells and, while cell structure varies dramatically from one organism to another, all cells share many common features (e.g. plasma membranes, genetic material, enzyme systems, receptors, membrane transport systems, etc.). In trying to define what we mean by "life", this structural difference serves us well. If you look throughthe microscope and see cells, you are certainly looking at a biological creature. But is it alive? How do you distinguish living cells from dead cells? Living creatures from deadcreatures? Well, okay, dead creatures don't move, or vocalize, or breathe, or eat -- i.e. they can't do anything. Doing something requires the contraction of muscles, the beating of cilia or flagella, or thesecretion of products. In addition, as far as we can tell, dead creatures don't sense anything. They don't see, hear, feel, or taste. That is, they have no "sensory function." And, again, as far as we living types know, dead creatures don't think about anything or have any emotions -- they don't remember, plan, enjoy, problem-solve, love, hate or do homework. If you look for the common denominator in all these activities -- moving, sensing, thinking and feeling -- you find that they all require ENERGY. Only living creatures can use energy to accomplish these things, these characteristics of life. You can have the structure of a biological creature, but without energy, you cannot be alive. Energy is an odd and sometimes hard thing to study. It's much less tangible than matter, which you can see, weigh, and measure directly. The effects of energy are manifested in movement (e.g. actin and myosin filaments sliding past one another, ions traveling up their concentration gradient) or in increases in temperature. We also have sense organs that can sense the presence of certain kinds of energy. For instance, our eyes can detect the presence of electromagnetic radiation with wavelengths between 380 and 750 nm (visible light). Our ears can detect the vibration of the air at certain frequencies (sound waves). However, we have no sense organs for many forms of energy including radio waves (your radio receiver can detect these, but you can't), radioactivity (a Geiger counter can detect these, but you can't) or neutrinos (they are passing through you right now, but youcan't sense them.) So, what is energy anyway? Focused Reading: p 28 Most biological…” stop at “Acids, Bases…”p 25-6 " Chemical Reactions…" stop at "Water:…" p 95-99 "Energy conversions…" stop at "Chemical reactions…"114Energy is the capacity to do work. In order for this definition to make sense, you must think of work in the very broadest sense of the word -- work is anything that changes the position or state of matter. Matter at absolute zero (no energy) is absolutely still and immutable -- no movement or change of any kind. Any movement or change in the structure of matter requires the input of energy. And that is how energy is defined. It's circular reasoning, but reasoning all the same. That which moves or changes matter is energy. And ENERGY IS MEASURED BY THE AMOUNT OF MOVEMENT OR CHANGE IN MATTER THAT IS PRODUCED. Big change or big movement equals big energy. Little change or little movement equals little energy. In many ways, this is just common sense. Does it take energy to move a barge up river? Yes. Does it take more energy to move a large barge than to move a small sailboat? Yes. Does it take more energy to move a barge up river than down river? Yes. Energy and matter functioning on the molecular level are NO DIFFERENT. Does it take energy to move a molecule across a cell membrane? Yes. Does it take more energy to move a big molecule than to move a small one? Yes. Does it take more energy to move a molecule up its concentration gradient than down its concentration gradient? Yes. Concepts,


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