BSCI 230 Today, 2/20/01

Lecture 7
Exam 1 in one week
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Questions?
Don't forget eCell for those late night questions
Get out your metabolism handout
And our demotivational thought for the day . . . .

 

Review

Glycolysis
Oxidation of Pyruvate
Ac-CoA into TCA Cycle
Remember:
ATP by SLP
ATP by chemiosmosis

 

Tricarboxylic Acid Cycle
Step 1:

Acetyl CoA (2C) + Oxaloacetate (4C) --->
        Citrate (6C) + CoA-SH
We looked at Fig 14-8 noting steps from pyruvate into cycle as citrate
Electron Transport System
Look at Figs 14-6, -17, -18
Know sequence of complexes and cytochromes from NADH and from FADH2
  • NADH - ->Complex I - -> Cyto Q - -> Complex III - -> Cyto C - -> Complex IV - ->
    •    O2(which is reduced to become water)
  • FADH2 - -> Complex II - -> Cyto Q - -> etc. as above

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    F0F1 - ATP Synthase (ATPase)

    Subunits: see Table 14-4
    F0 = proton translocator
    F1 = ATP synthase activity
    See Figs 14-21, -22, -23 and Table 14-4

     

    If you understand Fig 14-23, you are in good shape!

    Summary:
    C6H12O6 + 6H2O<---> 6CO2 + 6 H2O

    NADH + H+
    2 in Glycolysis
    2 in oxidation of pyruvate
    6 in TCA Cycle
    FADH2
    2 in TCA Cycle

     

    Summary:
    C6H12O6 + 6O2<---> 6CO2 + 6 H2O

    ATP by SLP
    4 total, 2 Net in Glycolysis
    2 in TCA Cycle
    ATP by Chemiosmosis
    32
    TOTAL ATP from Glucose = 38
    NET ATP from Glucose = 36

     

    Major Regulators of TCA Cycle

    Inhibitors:
    ATP
    NADH
    Acetyl CoA
    Activators
    ADP
    NAD+
    CoA-SH

     

    TCA Cycle as the Hub of Metabolism

     


     
     
     
     
     

    Photosynthesis: Chapter 15

    Photosynthesis
    Phototrophs
    Solar energy into ATP
    Photoheterotrophs
    Depend upon organic molecules for reduced C
    Photoautotrophs
    Solar energy to reduce C into organic molecules
    6 CO2 + 6 H2O ---> C6H12O6 + 6 O2
    Reduction of C
    Also called ìfixingî or assimilating Carbon
    DH ? - positive
    DS ? - decreasing
    DG ? - Positive
    Synthetic; anabolic; endergonic

     

    Photosynthesis

    Energy Transduction in the LIGHT reactions

    Sunlight ---> Chemical energy (ATP)
    Reducing power in the form of high energy electrons

     

    Carbon assimilation in the Dark reactions of the Calvin Cycle

    Photosynthesis: Remember that it requires:
  • Energy as ATP
  • Reducing power as e- carried by NADPH
  • 6 CO2 + 6 H2O ---> (CH2O)6 + 6 O2

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    SEE FIGS 15-5 AND 15-6
     

    Two Photosystems

    Photosystem II

    P680
    Light energy --> e- --> Pump protons (H+)
    Photosystem I
    P700
    Light energy --> e- + NADP+ --> NADPH