Version 039 – EXAM 3 – sathasivan – (48475) 1 This print-out should have 50 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points Why do plants use visible (light) part of the electromagnetic spectrum to do photosynthe- sis and not the areas of spectrum with shorter (UV and below) or longer wavelength (IR and above)? 1. Visible spectrum is prefered by the pro- teins in Calvin cycle. 2. UV light and IR spectrum are more dam- aging than visible light. 3. Visible spectrum is weaker than IR and safer than UV spectrum. 4. Visible light has the optimum level of energy and safety to perform photosynthesis. correct Explanation: Visible light spectrum is safer than UV and shorter wavelnegths and at the same time has more energy than IR and longer wavelength of the electromagnetic spectrum. 002 10.0 points Assuming only forward reactions, which of the following best depicts a diagram of en- zymes and substrates when they react? In the reactions, E = enzyme, S = substrate, ES = enzyme-substrate complex, P = products. 1. E + S → ES + P 2. E + P → EP → S + E 3. E + ES → P + E 4. E + P → ES 5. E + S → ES → E + P correct Explanation: Enzymes bind the substrate, form a transition-state complex, and release the product. 003 10.0 points All of the follwoing are directly associated with photsystem II except 1. P-680 2. reaction center chorophyll. 3. harvesting of light energy by chlorophyll and other pigments. 4. oxidativ phosphorylation. correct 5. release of oxygen. Explanation: 004 10.0 points Urea is a product of the metabolism of 1. All of these 2. proteins. correct 3. None of these 4. carbohydrates. 5. fats. Explanation: Urea results from protein degradation. 005 10.0 points Choose the sequence in which electrons move downhill during aerobic respiration. 1. glucose → ATP → oxygen 2. food → glycolysis → Krebs cycle → NADH → ATP 3. glucose → ATP → electron transport chain → NADH 4. food → Krebs cycle → ATP → NAD +

Version 039 – EXAM 3 – sathasivan – (48475) 2 5. food → NADH → electron transport chain → oxygen correct Explanation: The direction of flow of electrons during aerobic respiration is as follows: food → NADH → electron transport chain → oxygen. 006 10.0 points The bacterial genome exists as 1. a single, linear, uncoated, double- stranded DNA molecule. 2. a single, circular, protein-coated, double- stranded DNA molecule. 3. many circular, uncoated, double-stranded DNA molecules. 4. a single, circular, uncoated, double- stranded DNA molecule. correct 5. a single, circular, uncoated, double- stranded RNA molecule. Explanation: Recall 007 10.0 points Consider the reaction A + B → C + D be- low. a b c d e A+B C+D Reaction Progress Free Energy Which of the following will have the highest level of free energy?