MCB3020 Practice exam 3

Questions with *** next to it are questions that I made. Questions without it are from an old exam provided by Dr. A. Happy studying (and/or cramming) if possible!

1. In the redox reaction between H2 and O2, which of the following is true? ***a. The reduction potential of oxygen is more positive than hydrogen, therefore it will

accept electrons.b. The reduction potential of oxygen is more negative than hydrogen, therefore it will

donate electrons.c. The reduction potential of hydrogen is more negative than hydrogen, therefore it will

accept electrons.d. The reduction potential of hydrogen is more positive than hydrogen, therefore it will

donate electrons.

2. Adding a phosphate to:a. An acid makes a high energy phosphoanhydride bondb. An alcohol makes a high energy ester bondc. Glyceraldehyde-3-phosphate makes a low energy bondd. An acid makes a low energy ester bonde. Both C & D

3. Which of the following is incorrect about chemoorganotrophs?a. Are all heterotrophsb. Includes humans and animalsc. Do not compete with chemolitotrophsd. Receives energy from organic chemicalse. Do not use fermentation for energy

4. Erythrose 4-phosphate (E4P) and phosphoenolpyruvate (PEP) are used to make the aromatic amino acids. Which of the following is/are correct?

a. Through many reactions, they form chorismiteb. E4P and PEP are two of the 12 carbon skeletons needed to make all the building blocks

in prokaryotesc. Formation of the aromatic amino acids occurs during the fueling phase of metabolismd. All of the abovee. Both A & C

Use the following information for the next two questions: The redox potential of one redox pair is -0.45 (X/X-1) and the other redox pair is -0.17 (Y+1/Y).

5. Which one is being oxidized?a. Xb. Yc. Y+1

d. X-1

6. What is the free energy change if the equivalents of e- equals to 2?a. (2)(23)(-0.62)kcalb. -(2)(23)(-0.38)kcalc. -(2)(23)(-0.62)kcald. (2)(23)(-0.38)kcale. -(2)(23)(0.28)kcal

7. Select all that apply. An organism that is classified as a chomoorganoheterotroph would: ***a. Obtain energy from reduction of chemical compoundsb. Use organic molecules as carbon sourcesc. Use CO2 as their principal carbon sourced. Also be classified as a chemoheterotroph

8. Which of the following is paired correctly? ***a. Pyruvate → Acetyl CoA; FADH2

b. Acetyl CoA → Citrate; GTP or ATPc. Succinate → Fumarate; NADH2

d. Isocitrate → α-ketoglutarate; CO2

9. What is the TOTAL number of ATP produced from the Embden-Meyerhof Pathway? ***a. 2 ATP b. 4 ATPc. 30 ATPd. No ATP is produced in the Embden-Meyerhof Pathway

10. Fermentation:a. Produces 2 net ATPb. May produce lactatec. Both SLP and OP are used to make ATPd. All of the abovee. Both A & B

11. The electron transport chain: ***a. Only produces 4 ATP moleculesb. Synthesize ATP from NADH and FADH2

c. Has oxygen as the terminal electron acceptor in anaerobic respiration.d. Has electrons flow from carries with a more positive reduction potential to a carrier with

a more negative reduction potential.

12. You are studying a eukaryotes electron transport chain. Which of the following would you expect to be true? ***

a. Complex II is shuttling H+ outside of the matrix.b. Coenzyme C and Cytochrome Q are carrying electrons across the inner mitochondrial

membrane

c. Electron transfer is accompanied by proton movement across the inner mitochondrial membrane

d. B and C

13. Which of the following is correct regarding the Entner-Doudoroff pathway? ***a. It’s used by soil bacteria and a few eukaryotesb. It yields 1 ATP, 1 FADH, and 1 NADHc. 2-keto-3-deoxy-6-phosphogluconate (KDPG) is used to make pyruvate and

glyceraldehyde 3-phosphate d. A and Be. B and C

14. Select all that apply. The Pentose Phosphate Pathway, ***a. Is also called hexose monophosphate pathwayb. Can operate at the same time as glycolysis but not Entner-Doudoroffc. Can be used under both aerobic and anaerobic conditionsd. Can only be used in prokaryotes

15. During respiration, how is most of the energy made? ***a. SLPb. EMPc. OPd. ED

16. Which of the following produces 8 ATP?a. OP from Kreb’s cycleb. SLP and OP from Kreb’s cyclec. SLP from glycolysisd. SLP and OP from glycolysise. OP from fermentation

17. Of the following, which yields the highest energy upon hydrolysis of one of its energy yielding bonds?

a. Phosphoenolpyruvateb. ADP-->AMPc. Glucose-6-phosphated. Acetyl-CoAe. ATP-->ADP

18. Which of the following is/are true regarding the heme group found in cytochrome c?a. Binds loosely to cytochrome c because it is a coenzymeb. Contains a redox site with Fe+3/Fe+2c. It is a prosthetic groupd. None of the above

e. Both B & C19. Which of the following is/are the main products of fueling needed for biosynthesis?

a. The presence of chaperonesb. 12 carbon skeletons made in the 3 central pathwaysc. Activated building blocksd. All of the abovee. Both A & B

20. If one acetyl-CoA molecule is oxidized, TCA cycle generates all of the following except: ***a. 3 molecules of NADHb. 1 GTPc. 2 molecules of CO2

d. 1 FADH2

e. 2 ATP

21. Which of the following is incorrect?a. Acetyl-CoA has a high energy thioester bondb. The rate of a reaction cannot be changed by the presence of a catalystc. Pyruvate can be reduced by NADH to lactate during fermentationd. The elements C H O N P S make up close to 95% of a cell’s dry weighte. Obligate anaerobes can only grow in the absence of oxygen

22. Which of the following is incorrect? ***a. The First Law of Thermodynamics says that Energy can be neither created nor destroyedb. The First Law of Thermodynamics says that energy may be redistributes either within a

system or between the system and its surroundingsc. The Second Law of Thermodynamics says that physical and chemical processes proceed

in such a way that the disorder of the universe decreasesd. Entropy is the amount of disorder in a systeme. All of the following are correct

23. Select all that apply. In a spontaneous reaction: ***a. The ΔGo’ is negativeb. The reaction is endergonicc. The ΔGo’ is positived. The reaction is exergonic

24. Which of the following is correct?a. Glucose-ADP is the activated form of the sugar and it can be used to form a

polysaccharideb. E. coli can make all 5 nucleotides it needsc. ATP has three high energy bondsd. The reaction between H2 and O2 is not favorablee. There is no energy input necessary during the preparatory stage of glycolysis

25. Which of the following is incorrect? ***a. For an oxidation reaction to occur, a reduction reaction is also necessaryb. A more negative E0 is a better electron acceptorc. The oxidant gains electronsd. When writing a half reaction, the oxidizing reaction shows the electron being donated

26. Which of the following is correct about the EM pathway/glycolysis?a. Part of the energy provided by the reduction of glyceraldehyde-3-phosphate is used to

make a high energy bondb. NAD+, the oxidized form of the coenzyme, causes the oxidation of glyceraldehyde-3-

phosphatec. NADH, the oxidized form of the coenzyme, causes the reduction of glyceraldehyde-3-

phosphated. NAD+, the reduced form of the coenzyme, causes the oxidation of glyceraldehyde-3-

phosphatee. NADH, the reduced form of the coenzyme, causes the reduction of glyceraldehyde-3-

phosphate

27. In the electron transfer chain:a. The redox potential plays no role in determining the amount of energy produced during

electron transferb. The redox potential of pairs at the beginning of the chain are more negative than those

at the end of the chainc. The transfer of electrons through the chain produces a high concentration of protons

inside the celld. All carriers present are electron carriers onlye. Both B & D

28. Which of the following is/are correct about the electron tower? ***a. CO2/glucose have the most negative ΔE0’ valueb. ½ O2/H2O have the most positive ΔE0’ valuec. The further the electrons drop, the greater the amount of energy releasedd. ΔE0’ is proportional to ΔG0’e. All of the above

29. Which of the following is correct?a. A very negative free energy change for a reaction determines that it will go fast towards

the formation of the productb. Free energy calculations determine the speed/velocity of the reactionc. Activation energy determines the equilibrium concentration of reactants and productsd. The presence or absence of an enzyme changes the equilibrium constante. None of the above

30. Select all that apply. For a spontaneous reaction: ***a. ΔG is <0b. ΔE is <0c. ΔG is >0d. ΔE is >0e. ΔG and ΔE are both 0

31. Which of the following do NOT affect the reaction rate of an enzyme? ***a. Substrate concentrationb. pHc. Temperatured. All of the above affect the reaction rate

32. E0’: (select all that apply)a. Is measured in kcalb. The tower lists the reduction potential for the half-reactions written as an oxidation

reactionc. Can be used to calculate the free energy change by using Faraday’s equationd. More negative values are found at the bottom of the tower, they “catch” dropping

electronse. The greater ΔE0’ is, the less amount of free energy is available from the redox reaction

33. Which of the following is correct?a. Glycolysis requires the presence of oxygenb. Most of the ATP from aerobic respiration come from oxidation of NADH and FADH2

made during Kreb’s cyclec. For every one glucose, three pyruvates are made in glycolysisd. All of the abovee. Both A & B

34. Following the oxidation of pyruvate, which of the following is made? ***a. Acetyl-CoAb. Citratec. Succinated. α-ketoglutarate

35. Coenzymes (select all that apply):a. Bind to enzymes by strong covalent bondsb. Can only shuttle electrons, never protonsc. Help shuttle electrons from glycolysis to the electron transport chaind. Are often vitamin derivativese. Includes NAD+/NADH + H+

36. Which of the following is correct about enzymes?

a. The enzyme speeds up the velocity of a reaction and changes the equilibrium concentrations of the reactants and products

b. Have an active binding site for the substrate and a different binding site for the coenzyme

c. Increase the velocity of a reaction significantly by lowering the energy of activation to 20-30kcal, which can be supplied by free energy of motion at physiological temperatures

d. When binding to substrate the binding is more like a lock and key rather than induced fite. Are used up during the reaction with the substrate when forming the product

37. How many carbons does acetyl-CoA have? ***a. 1b. 2c. 3d. 4e. 5

38. Select all that apply. When going from α-ketoglutarate to succinyl-CoA what is produced? ***a. NADHb. FADH2

c. ATPd. CO2

e. GTP

39. Which of the following is not paired correctly? ***a. Heterotroph – organic molecules as carbon sourcesb. Phototrophs – use lightc. Lithotrophs – used oxidized inorganic substancesd. Autotrophs – use CO2 as their carbon sourcee. Chemotrophs – obtain energy from the oxidation of chemical compounds

40. Bacterial and Archaeal ETC: ***a. Are located in the plasma membraneb. Have different electron carriers than mitochondrial ETCc. May be branchedd. May be shortere. All of the above

41. The reaction A + B --> C + D has a ΔG of +50kcal under standard conditions. Which of the following is correct?

a. The reaction is spontaneous in the direction writtenb. The reaction is fast under standard conditionsc. The reaction is an endergonic reactiond. If an enzyme catalyst is present, the Keq is changed

e. None of the above

42. Which of the following is a good terminal electron acceptor for anaerobic respiration?a. CH4

b. O2

c. SO4-2

d. All of the abovee. Both A & C

43. Which of the following is true regarding the chemiosmotic hypothesis? ***a. Electrons move outward from the mitochondrial matrix as protons are transported

down the chainb. A concentration gradient is made from the expulsion of electrons as the protons will be

attracted to their chargec. As protons are pumped out of the cell or inner matrix of the mitochondria, it becomes

more alkaline and positived. None of the above are truee. All of the above are true

44. After glycolysis, what is the NET ATP produced? ***a. 1b. 2c. 3d. 4e. 5

45. Select all that apply. During Fermentation: ***a. Oxidation of NADH/FADH2 produces ATPb. Pyruvate acts as the electron acceptorc. Oxygen is not neededd. ATP is formed by SLP only

46. When the ATP synthases spins clockwise: ***a. H+ is transported outside and ATP is producedb. H+ is transported outside and ADP is producedc. H+ is transported inside and ATP is producedd. H+ is transported inside and ADP is produced

47. A negative allosteric effector works by: ***a. Non-covalently binding to the regulatory site to increase enzyme activityb. Non-covalently binding to the regulatory site to decrease enzyme activityc. Non-covalently binding to the active site to increase enzyme activityd. Non-covalently binding to the active site to decrease enzyme activity

48. Sulfa drugs are an example of what? ***a. Competitive inhibitorsb. Noncompetitive inhibitorsc. Allosteric inhibitorsd. Feedback inhibitors

49. Which of the following is paired correctly? ***a. Cofactor – metal ion or organic moleculeb. Prosthetic group – loosely attachedc. Coenzyme – firmly attachedd. Holoenzyme – cofactor + substrate

50. Photosynthesis: ***a. Is a two-part processb. Has both light reactions and dark reactionsc. During the light reaction, converts light to chemical energyd. A and Be. All of the above

51. How do you feel about this exam? ***1. I’ve been lost since day 12. I’m not feeling too good3. It could go good or bad4. I feel pretty good5. I’m going to rock this test