Bio102 Problems

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					                                          Bio102 Problems
                                           Photosynthesis

1. Why is it advantageous for chloroplasts to have a very large (in surface area) thylakoid membrane
   contained within the inner membrane?
   A. This limits the amount of stroma volume, keeping the concentrations of enzymes and substrates
       very high.
   B. This allows faster passive transport of small carbohydrates.
   C. This allows the organelle to have more copies of photosystems I and II and ATP synthase.
   D. The larger membrane improves its fluidity.
   E. This makes a more effective barrier to prevent protons from leaking through.

2. At the end of the electron transport chain found in the thylakoid membrane, the electrons are
   transferred to a molecule of
   A. H2O.
   B. NADP+.
   C. O2.
   D. Glucose.
   E. ADP.

3. For the electron transport chain used in photosynthesis,
               the initial electron donor is __water________________,
               the final electron acceptor is __NADP+___________,
               and the electron has gained/lost energy during transport.

4. Identify the metabolic process (such as fermentation,  -oxidation, etc.) that transfers energy from
   the molecule(s) listed in the column on the left to the molecule(s) listed in the column at right. List
   only one process in each empty box.
                AcCoA                  Citric Acid Cycle             ATP, NADH and FADH2

            ATP and NADPH
                                     Calvin-Benson Cycle                     Glucose
                                   (or Light-Independent Reactions)
                 Glucose                   Glycolysis                 NADH, ATP and Pyruvate
            NADH and FADH2             Electron Transport                Proton Gradient
             Proton Gradient             Chemiosmosis                         ATP
                Pyruvate                 Transition Step                NADH and AcCoA
                 Sunlight          Light-Dependent Reactions             NADPH and ATP

5. 2-carboxyarabinitol-1,5-bisphosphate (CABP) is an inhibitor of the Calvin cycle.
       5A. Which one of the following enzymes might CABP inhibit?
            A. Hexokinase
            B. ATP synthase
            C. Citrate oxidase
            D. RuBisCo
            E. Pyruvate decarboxylase
       5B. Why does treating chloroplasts with CABP eventually also cause the light-dependent
            reactions of photosynthesis to cease?
             NADP+ can’t be regenerated without the Calvin cycle.

6A.    A drawing of a chloroplast is shown below. Draw an arrow that points to the compartment
       where the light-independent
       reactions of photosynthesis
       occur and write the name of
       this compartment below.
        Stroma
6B. During the light-dependent
                                              *
       reactions of photosynthesis,
       protons (H+) are actively
       transported across a
       membrane. Draw a star in the compartment that becomes more acidic and write the name of that
       compartment below.
        Thylakoid Lumen
7. Each of the following three proteins or processes resides in a membrane and transports electrons.
     For each, identify the specific membrane where it is found and identify the molecule that donates
     the electrons to be transported.
          Protein or Process            Membrane:                     Electron Donor:
                                     Mitochondrial Inner
                    Complex I                                             NADH
                                         Membrane
                                     Mitochondrial Inner
                   Complex II                                             FADH2
                                         Membrane
             Light-Dependent
                                    Thylakoid Membrane                    Water
                    Reactions

8. Which one of the following is a reduced coenzyme that is synethsized in the Light-Dependent
        Reactions?
    A. FADH2
    B. FAD
    C. NADP+
    D. NADPH
    E. NADH
    F. NAD+

9. In a plant cell, where do the Light-Independent Reactions occur?
    A. Stroma
    B. Cytosol
    C. Matrix
    D. Intermembrane Space (IMS)
    E. Thylakoid Lumen
10. Name the carbon-containing molecule(s) that result from each of the following processes. Also
    indicate if these carbon atoms are being oxidized, reduced or neither in these processes.
    Process:                         Carbon-Containing Product(s):             Redox:
       Light-Independent
                                                 Glucose                           ox. red. neither
                Reactions
          Transition Step                       Acetyl-CoA                         ox. red. neither
               -oxidation                      Acetyl-CoA                         ox. red. neither
             Fermentation
                                                 Lactate                           ox. red. neither
              (in animals)
        Citric Acid Cycle                          CO2                             ox. red. neither
                Glycolysis                       Pyruvate                          ox. red. neither


11. Indicate whether each of the following statements describes electron transport on the mitochondrial
     inner membrane (MIM) or the light-dependent reaction of photosynthesis on the thylakoid
     membrane (TM) or both or neither by circling your choice.

                 The initial electron donor is a water
                                                            MIM     TM      both   neither
                 molecule.
                 The membrane must be fluid to
                                                            MIM     TM      both   neither
                 allow protein complexes to move.
                 Electrons flow from a high energy
                                                            MIM     TM      both   neither
                 state to a low energy state.

                 A reduced coenzyme is produced.            MIM     TM      both   neither

                 Energy is stored in a proton
                                                            MIM     TM      both   neither
                 gradient.
                 The electrons must pass through
                                                            MIM     TM      both   neither
                 Complex IV.

12. For each process listed below, identify the coenzyme (or coenzymes) that are required. Then
    indicate if the coenzyme(s) is oxidized, reduced or neither. Similarly, identify the carbon-
    containing molecule that is produced by the process and indicate if those carbon atoms have been
    oxidized, reduced or neither during the process.
                                                                         Carbon-Containing
Process                   Coenzyme(s)                    Redox               Product(s)               Redox
                                                         Oxidized                                     Oxidized
Calvin Cycle     NADPH                                   Reduced    Glucose                           Reduced
                                                          Neither                                      Neither
Citric Acid                                              Oxidized                                     Oxidized
                 NADH, FADH2                             Reduced    CO2                               Reduced
Cycle                                                     Neither                                      Neither
                                                         Oxidized                                     Oxidized
Fermentation     NADH                                    Reduced    Lactate                           Reduced
  (in animals)                                            Neither                                      Neither
                                                         Oxidized                                     Oxidized
Glycolysis       NADH                                    Reduced    Pyruvate                          Reduced
                                                          Neither                                      Neither
Transition                                                Oxidized                                  Oxidized
                 NADH                                     Reduced     Acetyl-CoA                    Reduced
Step                                                       Neither                                   Neither



13. Metabolic pathways represent a mechanism to transform energy from one source to another. For
each of the following processes, identify the high-energy molecule (or molecules) present both before
and after the process.
     High-Energy Molecule(s)                                                 High-Energy Molecule(s)
      BEFORE the Process                          Process                      AFTER the Process
             Acetyl-CoA                        Citric Acid Cycle                 NADH, FADH2
                                           Electron transport from
                light                  Photosystem II to Photosystem I
                                                                                      electron
                                           Anaerobic Metabolism
              Glucose                            (in humans)
                                                                                   ATP, Lactate
          Proton Gradient                       ATP Synthase                           ATP
           NADPH, ATP                   Light-Independent Reactions                   Glucose


14. Which one of the following is a key enzyme in photosynthesis?
    A. AMPK
    B. RuBisCo
    C. PFK
    D. Hexokinase
    E. Citrate Synthase

15. For each statement below, indicate if it is true for electron transport that happens in mitochondria,
electron transport that happens in chloroplasts, both or neither by circling your choice.

      The electron transport chain is located on the
                                                              Mitochondria   Chloroplasts   Both   Neither
      Inner Membrane.

      Water is reduced to form molecular oxygen.              Mitochondria   Chloroplasts   Both   Neither

      A coenzyme is oxidized.                                 Mitochondria   Chloroplasts   Both   Neither

      Protons are moved by active transport.                  Mitochondria   Chloroplasts   Both   Neither

      Electron transport relies on a functional antenna
                                                              Mitochondria   Chloroplasts   Both   Neither
      complex
      Energy is stored by making one compartment of an
                                                              Mitochondria   Chloroplasts   Both   Neither
      organelle more acidic.

16. Follow the Carbon! For each process listed below, list what carbon containing compound(s) are
put in and what carbon containing compound(s) come out. Also indicate the relative numbers for each
process except  -oxidation. The first one is done as an example.

                        Input                     Process                    Output
                           Glucose                       Glycolysis                      2 Pyruvate

                                                      Citric Acid Cycle                      CO2
                           AcCoA
                                                        Fermentation
                                                                                       Ethanol + CO2
                          Pyruvate                   (in fungi or plants)

                                               Light-Independent Reactions                Glucose
                             CO2
                                                      Transition Step                   AcCoA + CO2
                          Pyruvate
                                                        -Oxidation
                         Fatty acids

17. Name one process or pathway that stores energy in each of the following molecules. Notice that
     there may be more than one correct answer for each blank; just choose any one that is correct.

                                                                stores energy in FADH2
                     _______Citric Acid Cycle_________
                                                                stores energy in ATP
                         ________Glycolysis__________
                                                                stores energy in a H+ gradient
                    __________ Electron Transport____
                                                                stores energy in AcCoA
                    __________ Transition Step ______
                                                                stores energy in NADPH
                     __ Light-Dependent Reactions____
                                                                stores energy in Glucose
                    ____ Light-Independent Reactions _
                                                                stores energy in NADH
                     _______ Citric Acid Cycle ________
                                                                stores energy in GTP
                     _______ Citric Acid Cycle ________


18. List the high-energy molecules that are produced by each of the following processes. There may be
more than one correct answer; list all that apply. It is not necessary to list the number of each molecule formed.

               Citric Acid Cycle: NADH, FADH2, ATP

               Glycolysis: ATP, NADH, Pyruvate

               Transition Step: NADH, AcCoA

               -oxidation: AcCoA, NADH

               Light-dependent reactions: NADPH, ATP
19. Classify each of the following reactions as an oxidation reaction, a reduction reaction, both or
neither.

        NADP+ → NADPH                                 Oxidation      Reduction   Both    Neither


        ADP + PO4 → ATP                               Oxidation      Reduction   Both    Neither


                                                      Oxidation      Reduction   Both    Neither


        Pyruvate → Ethanol + CO2                      Oxidation      Reduction   Both    Neither


        4 H+ + O2 → 2 H2O                             Oxidation      Reduction   Both    Neither



20. For each carbon-contain molecule listed on the left, indicate which pathway (or pathways) in
    which it is produced. List all that apply.
                                                         A Alcoholic Fermentation
                                                         B -Oxidation

               __B I______    Acetyl-CoA (AcCoA)         C Citric Acid Cycle

                __A C I____   CO2                        D Deamination

               __A_______     Ethanol                    E Glycolysis

               __G_______     Glucose                    F Light-Dependent Reactions

               __E_______     Pyruvate                   G Light-Independent Reactions
                                                         H Receptor-Mediated Endocytosis
                                                         I Transition Step

21.    It’s obvious that the Light-Independent Reactions of photosynthesis can’t continue without the
high-energy molecules produced by the Light-Dependent Reactions. But would it be possible for the
Light-Dependent Reactions to continue if the Light-Independent Reactions were blocked? Why or why
not?
       No. If the light-dependent reactions were blocked, NADPH can’t be recycled to NADP+.
       Without NADP+, the electrons have no where to go in the light-dependent reactions thus
       causing them to shut down.

22. Which complex (or complexes) is correctly described by each of the statements below?
       List all that apply.

                                                                         A ATP Synthase

                                                                         B Complex I

                              Releases low energy electrons to O2.       C Complex II
             __E________
              Can transport protons against their
                                                    D Complex III
__B D E F__   diffusion gradient.
              Located in the thylakoid membrane.    E Complex IV
__A F G H__
              Contains chlorophyll.                 F Cytochrome Complex
__G H_____
              Oxidizes FADH2.                       G Photosystem I
___C_______
                                                    H Photosystem II

                                                    I None of these

				
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