Cell Biology 2085C Practice Exam PDF

Cell Biology 2085C – Practice Exam 1)Which of the following is NOT common to both eukaryotes and prokaryotes A. Ribosomes B. Mitotic spindle C. Nucleus D. DNA E. B and C 2). Different laboratory methods allow scientists to isolate specific cellular organelles, so that they can study...

Cell Biology 2085C – Practice Exam 1)Which of the following is NOT common to both eukaryotes and prokaryotes A. Ribosomes B. Mitotic spindle C. Nucleus D. DNA E. B and C 2). Different laboratory methods allow scientists to isolate specific cellular organelles, so that they can study some cellular processes in more detail. Which organelle would you try to isolate if you wanted to study the enzymes involved in lipid synthesis? A. Endoplasmic reticulum B. Mitochondria C. Golgi apparatus D. Lysosomes E. All of these options are correct 3). According to the theory of endosymbiosis promoted by ________, our earliest prokaryotic ancestor was an ________ , who ingested an _____ , the precursor of modern day mitochondria. Ingestion of a second endosymbiont, a _________, later evolved into chloroplasts. A. Lynn Margulis; Anaerobic heterotroph; Aerobic prokaryote; cyanobacteria B. Luis Pasteur ; Aerobic heterotrohoph; Aerobic prokaryote; cyanobacteria C. Lynn Margulis; Aerobic autotroph; Anaerobic prokaryote; cyanobacteria D. Robert Hooke; Aerobic heterotroph; Anaerobic prokaryote, amoeba E. Lynn Margulis; Anaerobic autotroph; Anaerobic prokaryote; algae 4). Which of the following is NOT a property of covalent and non-covalent bonds A. Covalent bonds are formed between atoms that make up a molecule B. Covalent bonds depend on shared electrons between atoms C. Non-covalent bonds require a large amount of energy to break D. Non-covalent bonds depend on attractive forces between atoms E. B, C and D. 5). Based on the following table of electronegativity, which of the following represents the order of polarity, most to least? A. C=O, O – H , C—N, C—H, C—C B. O=O, O—H, , C – C, C—H, C=O C. C=O, C—H, O=O, C – N, O—H D. C—S, O—H, C—N, C=O, C – C E. O – H , C=O, C—N, C—H, C—C 6). In a covalent bond formed between Nitrogen and a less electronegative atom, the N atom would have a _______ while the less electronegative atom would have a _______ charge. A. Partial positive; Partial negative B. Partial negative; Partial positive C. Positive; Negative D. Negative; Positive E. None of the above are correct 7) Particular groupings of atoms that often behave as a unit and give organic molecules their physical properties, chemical reactivity and solubility in aqueous solutions are known as: A. Amphipathic groups D. Kinetic groups B. Ionic groups E. Conformational groups C. Functional groups D. Kinetic groups 8). Which of the following characteristics below (from 1 to 7) are typical of the polysaccharide cellulose? 1. Polymer of glucose 5. Long, unbranched chains 2. Contains α (1—>4) glycosidic linkages 6. Branched, coiled chains 3. Contains β (1—>4) glycosidic linkages 7. Good source of fiber 4. Water soluble A. 1, 2, 4, 6, 7 D. 1, 3, 5, 7 B. 1, 3, 4, 5, 7 E. 1, 3, 5 C. 1, 2, 4, 7 9). Compounds rich in ________ tend to be liquid at room temperature. These compounds can be altered so they are solid at room temperature by ____________. A. Unsaturated fats; Decreasing the amount of double bonds B. Saturated fats; Decreasing the amount of double bonds C. Unsaturated fats; Decreasing the amount of single bonds D. Saturated fats; Decreasing the amount of single bonds E. Unsaturated fats; Increasing the amount of double bonds 10). The following structures represent ______, which are maintained _____ at room temperature, due to the ______ of double bonds. A. Saturated fats; Solid; Absence B. Unsaturated fats; Solid; Presence C. Saturated fats; Liquid; Presence D. Unsaturated fats; Liquid; Absence E. Saturated fats; Solid; Presence 11). A patient with hyperlipidemia has been counseled to reduce the saturated fats in his diet, so he has replaced butter with a butter substitute that he knows is made from a polyunsaturated oil. The manufacturer of this butter substitute has partially hydrogenated this product. Which one of the following is the best description of why this product was partially hydrogenated? A. The trans-fatty acids produced by commercial hydrogenation are very healthy in humans. B. Hydrogenation reduces the double bonds, creating a more saturated product, which is more marketable. C. Hydrogenation makes the product less expensive to produce. D. Hydrogenation reduces the cholesterol content of the oil. E. Hydrogenation increases the cholesterol content of the oil. 12). As a scientist you find an unknown sample and run some tests to identify this unknown sample. Molecular analysis found glycerol, fatty acids, phosphate and choline. Given this, which conclusion is most probable? A. It can be a sample of carbohydrate only. B. It can be a sample of phospholipid and fat. C. It is only phospholipid. D. It is only fat. 14) You treat a partially purified preparation of protein with mercaptoethanol, a reagent that can break bonds formed between sulfur atoms. Which level of protein structure is likely to be affected? A. Secondary B. Tertiary C. Quaternary D. C and D are correct E. A, B and C are correct 15). Amino acids 1 to 4 are all part of the same solution at a particular pH. If kept at the same pH, hydrogen bonds, could be formed between the R groups of: A. Between 1 and 2 B. Between 2 and 3 C. Between 1 and 3 D. Between 2 and 4 E. All of them are capable of forming hydrogen bonds 16). Amino acids 1 to 4 are all part of the same solution at a particular pH. If kept at the same pH, ionic bonds could be formed between the R groups of: A. Between 1 and 2 B. Between 2 and 3 C. Between 2 and 4 D. Between 3 and 4 E. None of these pairs is capable of forming ionic bonds unless pH is changed. 17). How many amino acids are in this peptide? A. Seven B. Eight C. Nine D. Ten E. Eleven 18). What is the role of misfolded proteins in Creutzfeld-Jakob Disease? A. Misfolded proteins act as infectious agents by inserting themselves in the host genome B. Misfolded proteins act as infectious agents by propagating their misfolded protein state C. Misfolded proteins accumulate around the ribosomes, making them unable to synthesize more proteins D. Misfolded proteins block activity of molecular chaperones HSP70 and HSP60 E. B, C and D are correct. 19). Free energy is ________. A reaction will be spontaneous when ________. A. The total energy of the system; The free energy of the reactants is lower than that of the products. B. The total energy of the system; The free energy of the products is lower than that of the reactants. C. The energy available to do work; The free energy of the reactants is lower than that of the products. D. The energy available to do work; The free energy of the products is lower than that of the reactants. E. The energy available to do work; The energy of activation is lowered by an decrease in the free energy. 20). Conversion of A  B is an endergonic reaction. Which of the following reactions could be coupled with AB so that both AB and C D can occur? A. C  D (ΔG = -5.4 kcal/mole) B. C  D (ΔG = +9.3 kcal/mole) C. C  D (ΔG = -10.2 kcal/mole) D. Both A and C E. None of the above 21). The continual flow of oxygen and other materials into and out of cells allows cellular metabolism to exist in a steady state because A. The concentrations of reactants and products fluctuate frequently. B. The concentrations of reactants and products change as the cell grows. C. The concentrations of reactants and products remain relatively constant. D. The concentrations of reactants and products in a living cell are always at equilibrium E. None of these statements are true 22). Enzymes speed up reactions by lowering the _______. This can be accomplished by forming an enzyme- substrate complex, where the R chains of the amino acids in the enzyme’s _____ and the substrate are bound together by _________ A. Activation energy; Transition state; Permanent covalent bonds B. Free energy; Transition state; Permanent covalent bonds C. Activation energy; Active site; Permanent covalent bonds D. Free energy; Active site; Noncovalent bonds E. Activation energy; Active site; Noncovalent bonds 23). Dissolving a sugar cube in water and breaking down complex glycogen molecules into smaller molecules are examples of decrease of entropy in a system A. True B. False 24). The amino acids glutamine and glutamic acid are shown below. They differ only in the structure of their side chains (circled). At pH 7, glutamic acid can participate in molecular interactions that are not possible for glutamine. What types of interactions are these? A. Ionic bonds B. Hydrogen bonds C. Van der Waals interactions D. Covalent bonds 25. Which of the following amino acids has side chains with the greatest potential to form a) hydrogen-bonds b) ionic-bonds and c) hydrophobic interactions? (assume you don’t change the pH) A. a) 4; b) 2; c) 1 B. a) 3; b) 1; c) 5 C. a) 2; b) 4; c) 5 D. a) 2; b) 5; c) 1 E. a) 1; b) 5; c) 3 26) You mix reagents (A, B, C, D) so that each is present at an initial concentration of 0.3M. The equilibrium constant for the reaction Keq is 2.8. Which choice represents the final concentrations of each reagent once equilibrium is achieved? A. [0.35] [0.35] / [0.25][0.25] B. [0.15][0.15] / [0.6][0.6] C. [0.02][0.02]/[0.9][0.9] D. [0.25][0.25] / [0.15] [0.15] E. [0.6][0.6] / [0.25][0.25] 27). What type of bond is this and what structure do long chains of this make up? A.Alpha1,4; Starch B. Beta1,4 Cellulose C. Alpha1,6; Starch D. Beta1,6; Cellulose 28). A fatty acid consists of three hydrocarbon chains linked to a glycerol backbone. A. True B. False 29). Is the following statement correct? “Amino acids used in making a polypeptide have an amino group and a carboxyl group, and these groups can be present on any carbon atoms”. A. Yes, when looking at the structure of amino acids we can see that these groups are attached to a carbon therefore they can be spread out on other carbons too. B. Yes, amino acids vary in size and can have multiple carbons in the backbone. C. No, amino acids require a very specific structure and must have all groups attached to the alpha carbon. D. No, amino acids require both groups to be attached to two different alpha carbons that are bonded together. 30). An enzyme in the liver that removes glucose from blood has a high KM; another that does the same thing in brain tissue has a small KM. Which of the following options would BEST describe how this information would relate to glucose uptake in an organism? A. The enzyme in brain tissue can take glucose from the bloodstream even when levels are low, and the enzyme in liver will not take glucose from blood unless levels are high B. The enzyme in brain tissue can take glucose from the bloodstream only when levels are high, and the enzyme in liver will not take glucose from blood at any time C. The values of KM alone are not related to how well an enzyme works under different substrate concentrations