Exam 2 Cellular And Molecular Biology

54 Questions

Settings
Please wait...
Exam 2 Cellular And Molecular Biology

Biol 218Exam 2Cellular and Molecular Biology


Questions and Answers
  • 1. 
    The sodium-potassium pump makes the cell interior more______ by pumping ____ sodium ions out of the cell for every____ potassium ions pumped in.
    • A. 

      Negative, 3, 2

    • B. 

      Negative, 2, 3

    • C. 

      Positive, 3, 2

    • D. 

      Positive, 2, 3

    • E. 

      Negative, 4, 3

  • 2. 
    • A. 

      It must be pumped during the cycle.

    • B. 

      It must be phosphorylated during the cycle

    • C. 

      It must be protonated during the cycle

    • D. 

      It must be deprotonated during the cycle

    • E. 

      It must be potassiumated during the cycle

  • 3. 
    In the Na+/glucose cotransporter, _____ moving down its/theirgradient drive the transport of _____ against its/their gradient.
    • A. 

      Na+ ions, K+ ions

    • B. 

      Na+ ions, glucose

    • C. 

      Glucose, Na+ ions

    • D. 

      K+ ions, glucose

    • E. 

      Glucose, K+ ions

  • 4. 
    • A. 

      Succinate dehydrogenase, mitochondrial matrix

    • B. 

      Malate dehydrogenase, mitochondrial matrix

    • C. 

      Succinate dehydrogenase, inner mitochondrial membrane

    • D. 

      Malate dehydrogenase, inner mitochondrial membrane

    • E. 

      Succinate dehydrogenase, intermembrane space

  • 5. 
    The movement of water through a semipermeable membranefrom a region of higher water concentration to a region of lowerwater concentration is called ________.
    • A. 

      Diffusion

    • B. 

      Osmosis

    • C. 

      Denaturation

    • D. 

      Metabolism

    • E. 

      Solubility

  • 6. 
    The phosphorylation of glucose to generate glucose-6-phosphate is catalyzed by the enzyme hexokinase. This enzyme,however, is inhibited by its own product, glucose-6-phosphate.This is an example of:
    • A. 

      Allosteric regulation

    • B. 

      Irreversible inhibition

    • C. 

      Non-covalent modification

    • D. 

      Feedback regulation

    • E. 

      Covalent modification

  • 7. 
    A protein extract containing an enzyme of interest is preparedfrom a tissue. The enzyme activity is tested using a panel ofsuspected substrates. However the enzyme is not active, leadingto the conclusion that none of the compounds is the enzyme’ssubstrate. One student of Biol218-003 suggests adding ATP tothe enzyme mixture. Suddenly a reaction is observed in one ofthe tubes. After adding ATP the enzyme was purified and one ofits aminoacids has a phosphate group. This is an example of
    • A. 

      Lucky guess

    • B. 

      Covalent modification of enzymes

    • C. 

      Activation of the enzymatic activity by a kinase

    • D. 

      B and c

  • 8. 
    A transport system that moves two solutes into the cell during asingle cycle accompanied by no expenditure of energy could becalled a(n) ________
    • A. 

      Active antiport

    • B. 

      Active uniport

    • C. 

      Passive antiport

    • D. 

      Active symport

    • E. 

      Passive symport

  • 9. 
    Feedback inhibitors bind to the
    • A. 

      Allosteric site

    • B. 

      Active site

    • C. 

      Substrate

    • D. 

      Cofactor

    • E. 

      A and b

  • 10. 
    The inner membrane of the mitochondria has a high protein tolipid ratio because it contains ____________.
    • A. 

      Electron transport chain

    • B. 

      ATP synthase

    • C. 

      Cardiolysin

    • D. 

      A and b

    • E. 

      A and c

  • 11. 
    What is the purpose of uncoupling proteins in mammalian brownadipose tissue (baby fat)?
    • A. 

      They help the tissue expand and contract when needed.

    • B. 

      They function as a source of heat production during exposure to cold temperatures.

    • C. 

      They allow the production of a larger number of ATPs per glucose.

    • D. 

      They allow muscles to contract more efficiently.

    • E. 

      They give the tissue its color.

  • 12. 
    Which molecule below plays a key role in regulating the rate ofglycolysis and Krebs cycle by regulating the activity of keyenzymes?
    • A. 

      ADP

    • B. 

      ATP

    • C. 

      Inorganic Phosphate

    • D. 

      Molecular oxygen

    • E. 

      None of the above

  • 13. 
    Metabolic pathways that make available raw materials fromwhich other molecules can be synthesized and that providechemical energy required for many cell activities are known as______.
    • A. 

      Anabolism

    • B. 

      Catabolism

    • C. 

      Manabolism

    • D. 

      Allosterism

  • 14. 
    A reaction involving the gain of one or more electrons is a(n)_________ reaction.
    • A. 

      Oxidation

    • B. 

      Reduction

    • C. 

      Inclusion

    • D. 

      Elimination

    • E. 

      None of the above

  • 15. 
    In order to take full advantage of the energy released during anexergonic reation, it is ______________.
    • A. 

      Done in small steps

    • B. 

      Used to drive the temperature of the cells up

    • C. 

      Coupled to an endergonic reaction

    • D. 

      Coupled to another exergonic reaction

  • 16. 
    Which of the following is the primary function of fermentation?
    • A. 

      Completely break down a glucose molecule to carbon dioxide and water

    • B. 

      Produce ATP by chemiosmosis

    • C. 

      Oxidize NAD+ to NADH

    • D. 

      Oxidize NADH to NAD+

    • E. 

      All of the above

  • 17. 
    • A. 

      E + F G + H (ÄG = -5.4 kcal/mole)

    • B. 

      C + F G + H (ÄG = -5.4 kcal/mole)

    • C. 

      E + F G + H (ÄG = -8.3 kcal/mole)

    • D. 

      E + F G + H (ÄG = -9.7 kcal/mole)

    • E. 

      None of them

  • 18. 
    The outer membrane of the mitochondria has large channelssurrounded by a Beta barrel called _________________.
    • A. 

      Proton pump

    • B. 

      Cardiolipin

    • C. 

      Porins

    • D. 

      Cytochrome complex

    • E. 

      ATP synthesis

  • 19. 
    The redox centers of most of the proteins of the respiratory chainare made up of _________________.
    • A. 

      Flavoproteins

    • B. 

      Vitamins

    • C. 

      Prosthetic groups

    • D. 

      Cytochromes

    • E. 

      Ubiquinone

  • 20. 
    An electrochemical gradient is caused by __________________.
    • A. 

      Energy distribution

    • B. 

      Voltage gradient

    • C. 

      Concentration gradient

    • D. 

      A and b

    • E. 

      B and c

  • 21. 
    Which molecule is the final electron acceptor in the electrontransport chain?
    • A. 

      ATP

    • B. 

      Water

    • C. 

      NADH

    • D. 

      Oxygen

    • E. 

      FADH2

  • 22. 
    Diffusion during which the substance to be transported bindsselectively to a membrane-spanning protein, which helps theprocess along, is called ________.
    • A. 

      Osmosis

    • B. 

      Facilitated Osmosis

    • C. 

      Simple Diffusion

    • D. 

      Facilitated Diffusion

    • E. 

      Active Transport

  • 23. 
    An important aspect of transport by facilitated transporters andpumps is
    • A. 

      Conformational shifts

    • B. 

      Rigidity softness

    • C. 

      á-helix

    • D. 

      B-pleated sheet

  • 24. 
    The site of aerobic respiration (electron transport chain) and ATPformation is in the _________________ of the Mitochondria.
    • A. 

      Outer membrane

    • B. 

      Matrix

    • C. 

      Inner membrane

    • D. 

      Intermembrane space

  • 25. 
    One mechanism (or class of molecules) by which ions arespecifically transported into the cell is the
    • A. 

      Induced fit model

    • B. 

      Gated channels

    • C. 

      Carrier protein transport

    • D. 

      Uniport transport

    • E. 

      All of the above

  • 26. 
    During strenuous exercise, you may notice that your musclesburn. Which of the following statements best explains thisphenomenon?
    • A. 

      Proteins are being digested to provide energy

    • B. 

      ADP is accumulating, which produces a burning sensation

    • C. 

      Without oxygen, pyruvate is being converted to lactic acid.

    • D. 

      Pyruvic acid causes muscle pain.

    • E. 

      Carbon dioxide is building up in muscle and changing the pH.

  • 27. 
    Of the following molecules, which would NOT be expected to bemoved across a membrane by simple diffusion?
    • A. 

      Fatty acids

    • B. 

      Glucose

    • C. 

      Oxygen

    • D. 

      Water

  • 28. 
    You are trying to figure out an electron transport pathwayincluding the following electron transport molecules: B, K, T Qand X. You do so by employing inhibitors for various steps in theprocess. When you do, you get the following results:Inhibitor                                Electron Transport Molecules Trapped in                                              Reduced FormTicin                                    Q& KDigitin                                  KEstin                                   T, K, Q & BLucin                                   Q, K & TWhat is the order of the molecules (the pathway) in the electrontransport chain suggested by the above data from the most reducedto the least reduced molecule?
    • A. 

      K¨ T ¨ B¨ Q ¨ X

    • B. 

      K ¨ X ¨ B ¨ Q ¨ T

    • C. 

      K ¨ Q ¨ T ¨ B ¨ X

    • D. 

      X ¨ B ¨ T ¨ Q ¨ K

    • E. 

      T ¨ B ¨ K ¨ Q ¨ X

  • 29. 
    A researcher is interested in the mode of transport across thecell membrane of three different substances: A, B, and C. Hisdata are reported in the graphs associated with the followingquestions. The graph above shows the initial rate of transport foreach substance, when the cells are placed in solutions ofdifferent concentrations of A, B, and C. Based on this data,substance A is transported via
    • A. 

      Simple diffusion

    • B. 

      Active transport

    • C. 

      Facilitated diffusion

    • D. 

      Passive transport

    • E. 

      A, b and c

  • 30. 
    • A. 

      Are transported by a transporter protein

    • B. 

      Do not move by simple diffusion

    • C. 

      Show saturation kinetics

    • D. 

      A and B only

    • E. 

      All of the above

  • 31. 
    The statement, "The total amount of energy in the universe isconstant," is a tenet (part or implication) of
    • A. 

      Thermodynamic spontaneity

    • B. 

      The second law of thermodynamics

    • C. 

      Enthalpy

    • D. 

      The first law of thermodynamics

    • E. 

      Entropy

  • 32. 
    • A. 

      The reaction is not spontaneous under standard conditions.

    • B. 

      There can be no reaction

    • C. 

      The reaction is at equilibrium under standard conditions

    • D. 

      Products predominate over reactants at equilibrium under standard conditions.

    • E. 

      The reaction goes spontaneously to the right under standard conditions.

  • 33. 
    A negative free energy change indicates that
    • A. 

      The reactant is predominant at equilibrium

    • B. 

      The reaction is not possible

    • C. 

      The reaction is at equilibrium

    • D. 

      Energy must be added to the reaction before it can proceed.

    • E. 

      The reaction is exothermic.

  • 34. 
    A spontaneous reaction
    • A. 

      Has to occur immediately.

    • B. 

      Is associated exclusively with homeothermic organisms

    • C. 

      Has an overall positive free energy change

    • D. 

      Will never occur

    • E. 

      Could occur, but might take a very long time.

  • 35. 
    When the TG°' of a chemical reaction is positive (K'eq < 1.0)under standard conditions,
    • A. 

      Work can be done under these conditions.

    • B. 

      Reactants predominate over products.

    • C. 

      Reactants and products are at equilibrium.

    • D. 

      The reaction is exothermic.

    • E. 

      The reaction is spontaneous to the right.

  • 36. 
    When TG' = 0 in a chemical reaction, under normal conditions
    • A. 

      Reactants and products are at equilibrium.

    • B. 

      The reaction is spontaneous to the left.

    • C. 

      Work can be done; energy is required.

    • D. 

      No work can be done; no energy is required.

    • E. 

      Both A and D

  • 37. 
    Which of the following is NOT an example of facilitated diffusion?
    • A. 

      Aquaporins

    • B. 

      Anion exchange protein

    • C. 

      Channel proteins

    • D. 

      Oxygen transport

    • E. 

      GluT1 glucose transporter

  • 38. 
    Which of the following is NOT a characteristic of passivetransport?
    • A. 

      The energy for transport is generated by the gradient of the substance being transported.

    • B. 

      The energy for transport is generated by the molecular bonds of the substance being transported.

    • C. 

      Transport of the substance is the result of a conformational change.

    • D. 

      It is specific for the molecule being transported.

    • E. 

      It requires binding of the molecule to be transported.

  • 39. 
    Which of the following is/are TRUE with regard to watermovement in osmosis?
    • A. 

      Hypertonic ¨ hypotonic

    • B. 

      Hypertonic ¨ isotonic

    • C. 

      Hypotonic ¨ hypertonic

    • D. 

      Isotonic ¨ hypotonic

    • E. 

      Both choices C and D

  • 40. 
    Covalent modification
    • A. 

      Can inactivate an enzyme

    • B. 

      Can activate an enzyme.

    • C. 

      Affects the activity of an enzyme by adding or removing a chemical group.

    • D. 

      Can involve the addition of phosphate groups.

    • E. 

      All of the above

  • 41. 
    The process of glucose synthesis is called
    • A. 

      Glucogeneration

    • B. 

      Glycolysis.

    • C. 

      Gluconeogenesis.

    • D. 

      Aglycolysis.

    • E. 

      Both B and C

  • 42. 
    Which of the following is NOT a product of the TCA cycle? 22)______
    • A. 

      Acetyl CoA

    • B. 

      FADH2

    • C. 

      ATP

    • D. 

      NADH

    • E. 

      Carbon dioxide (CO2)

  • 43. 
    Facilitated diffusion implies that energy in which form is NOTrequired?
    • A. 

      ATP

    • B. 

      Light

    • C. 

      Oxygen

    • D. 

      Glucose

  • 44. 
    • A. 

      Sweating removes prosthetic groups from biological enzymes.

    • B. 

      Enzymes do not function as well at temperatures other than the optimal temperature.

    • C. 

      Bacteria reproduce more rapidly at higher body temperature.

    • D. 

      The higher temperature increases the activity of lysases.

    • E. 

      Fever blocks synthesis of proteins in the bacterial nucleus.

  • 45. 
    Enzyme regulation may occur by several methods. Which of thefollowing is NOT a means of enzyme regulation?
    • A. 

      Allosteric regulation

    • B. 

      Covalent modification

    • C. 

      Feedback inhibition

    • D. 

      Substrate-level phosphorylation

    • E. 

      Saturation

  • 46. 
    • A. 

      NAD+ is used to carry electrons.

    • B. 

      NADH is used primarily in substrate-level phosphorylation.

    • C. 

      NADH is capable of pumping ions during glycolysis.

    • D. 

      NADH is used to produce energy by directly creating the phosphoanhydride bonds in ATP.

    • E. 

      All of the above

  • 47. 
    How does the sodium-potassium pump help to make the cell interiornegative?
    • A. 

      It pumps negative ions into the cell.

    • B. 

      It pumps 3 sodium ions out of the cell for every 2 potassium ions pumped in.

    • C. 

      It pumps 3 potassium ions out of the cell for every 2 sodium ions pumped in

    • D. 

      It pumps 3 sodium ions out of the cell for every 2 sodium ions pumped in.

    • E. 

      It pumps 3 potassium ions out of the cell for every 2 potassium ions pumped in.

  • 48. 
    The _____________ is when the reactants are ready to be convertedto product
    • A. 

      Activation barrier

    • B. 

      Enzyme-substrate complex

    • C. 

      Transition state

    • D. 

      Steady state

  • 49. 
    What kind of inhibitor binds tightly to the enzyme often forming acovalent bond with an aminoacid in the active site?
    • A. 

      Irreversible

    • B. 

      Uncompetitive

    • C. 

      Reversible

    • D. 

      Allosteric

  • 50. 
    • A. 

      Vmax stays the same, KM decreases

    • B. 

      Vmax decreases, KM is unchanged

    • C. 

      Vmax increases, KM is unchanged

    • D. 

      Vmax stays the same, KM is unchanged

    • E. 

      Vmax stays the same, KM increases

  • 51. 
    What is the distinguishing characteristic of a P-type pump?
    • A. 

      It must be deprotonated during the cycle

    • B. 

      It must phosphorylated during the cycle

    • C. 

      It must be pumped during the cycle

    • D. 

      It must be protonated during the cycle

    • E. 

      It must be potassiumated during the cycle

  • 52. 
    Transport system that moves 2 substances into the cell per cyclecould be called a(n) _____.
    • A. 

      Uniport

    • B. 

      Antiport

    • C. 

      Symport

    • D. 

      Transmembrane protein

    • E. 

      C and d

  • 53. 
    An example of potential energy is ________.
    • A. 

      A rock rolling down a hill

    • B. 

      A full gas tank in a car

    • C. 

      A rock perched on the edge of a cliff

    • D. 

      A thrown baseball on its way to home plate

    • E. 

      B and c

  • 54. 
    In Figure 5.18, if the pH inside the pictured liposome were 7.3, whichpH below would be most likely to be the pH registered by the pHelectrode pictured in the figure?
    • A. 

      9.4

    • B. 

      7.8

    • C. 

      6.2

    • D. 

      7.3

    • E. 

      10.9