Cell Structure and Function -- see previous review sheet
          Prokaryotic vs. Eucaryotic cells

Cell membrane - fluid mosaic model
     Components: 
            I.  Lipids
                     A.  Phospholipid bilayer
                      B.   cholesterol
            II.  Proteins
                     A.   Extrinsic/intrinsic proteins
                     B.   Filaments of the cytoskeleton
            III.  Carbohydrates
                              Glycocalyx in animal cells (cell-cell recognition) -- "fuzzy coat" of
                                 glycolipids/glycoproteins; each cell type unique

Junctions: Tight, Gap, Desmosomes, plasmodesmata

Cell membrane is semipermeable (selectively/differentially permeable)
         regulates movement of molecules into and out of cells

Transport of materials through membrane:
I.  Passive processes: No energy required
     A. Diffusion -- movement of atoms/molecules down a concentration gradient 
               Osmosis -- water (or some solvent) diffusing through a semipermeable membrane
                            water typically follows solutes if solutes are moved
                        Understand the meaning of hypo-/iso-/hypertonic solutions
     B. Facilitated diffusion -- uses carrier proteins to move substances with the gradient
II.  Active processes: Energy (ATP) required
     A.  Active transport -- also uses carrier proteins, but moves materials against the gradient
                 example: Na⁺ - K⁺ pump
     B.  Bulk Transport
           1.Endocytosis - bulk transport into the cell
                    a.  Phagocytosis
                    b.  Pinocytosis
                    c.  Receptor-mediated endocytosis
           2.  Exocytosis - Bulk transport out of the cell

Cell Energetics -- Energy Transformations (includes Photosynthesis and Cellular Respiration)
     Energy - capacity to do work (move matter)
            States: kinetic (in action) or potential (stored)
            Types - radiant (light), electrical, mechanical, chemical, thermal (heat)

Laws of Thermodynamics:
     1. First: Energy Finite (can=t be created or destroyed) but convertible
     2. Second: Every conversion increases entropy (some energy lost as heat during any conversion)

Chemical Reactions: all reactions require some initial input of energy (energy of activation -- E_a)
         Types:
            1. synthesis - requires a net input of energy               (endergonic)
            2.  degradation/decomposition - liberates energy       (exergonic)
            3.  exchange - energy balance depends on reactants (substrates) and products
    Concepts:   Endergonic/Exergonic reactions - Coupling of reactions;
                       Free energy of the reaction

Enzymes and Enzyme function: Virtually all reactions in the body require enzymes
    Enzymes:
        Do not change equilibrium of reactants (substrates) and products, or the free energy
        Do speed the rate of reactions (catalysts) by reducing the E_a (energy of activation)
    Active site
    Inhibitors - competitive/non-competitive; many enzymes inhibited by negative feedback

Reduction/Oxidation reactions (Redox): generally occur together
    reduction - gaining electrons/energy; oxidation - losing electrons/energy
                     protons (H+) often get passed with electrons
          Electron (energy) carriers :   NADPH + H⁺, NADH + H⁺ and FADH₂
See how these electron carriers are used in electron transport chains in both Photosynthesis and
Cellular Respiration, below, to help generate ATP

Photosynthesis - SEE OTHER HANDOUTS - anabolic set of reactions - synthesis of glucose
          Photosynthesis converts light energy to chemical energy

Leaves - main organ of photosynthesis (see also Chapter 33, page 718)
        upper/lower epidermis, with stomates for exchange of CO₂ (in)/water (out)
        pallisade/spongy parenchyma - photosynthetic (mesophyll); contains chloroplasts
             Chloroplasts have stroma/thylakoids

I.    The Light Dependent Reactions - cyclic/non-cyclic photophosphorylation
        Involves electron transport across the thylakoid membranes electrons excited by light energy
        H₂O is the initial electron donor (O₂ released); NADP⁺ is the final electron acceptor
        ATP formation (phosphorylation) coupled to movement of protons (H⁺=s) --
             Chemiosmosis - movement of protons through a semipermeable membrane

II.   The Light Indpendent Reactions or the Calvin Cycle (CC) -- The Carbon fixation steps
        These steps are responsible for fixing CO₂ into glucose, these steps don't require light
           . . . except to activate Rubisco ; in other words this enzyme is light-activated         
               Rubisco - Ribulose bisphosphate carboxylase/oxygenase
                     This enzyme (most abundant protein in the world) fixes CO₂ (and also O₂)
      A.  C₃ PS - Uses Calvin Cycle only; found in cool, moist adapted plants
      B.  C₄/CAM PS - Uses PEPC (phospho-enol pyruvate carboxylase) also
                PEPC is not light activated B when carbon dioxide first fixed, it is attached to a
                         four-carbon molecule; then passed to a different cell (bundle sheath)
                The fixed CO₂ is then released and refixed by Rubisco to make glucose in the CC
                In other words, these plants use a CO₂ shuttle, but still use CC to make glucose
                Found in warm, dry adapted plants
            CAM plants use PEPC, just like C₄ plants, but fix CO₂ at night to avoid water loss

Cellular Respiration - SEE HANDOUTS - catabolic set of reactions; breaks down glucose  
            to get energy; occurs in all organisms - plants, animals, etc.

I.  Glycolysis - in cytoplasm
        if anaerobic (no O₂), followed by fermentation - also in cytoplasm
        if aerobic (with O₂), followed by the following two sets of reactions . . .

II.  Krebs=/TCA (tricarboxylic acid)/Citric Acid Cycle
            pyruvate moves into inner matrix of mitochondria, where TCA cycle takes place
            requires decarboxylation (removal of CO₂) to form 2C Acetyl CoA to enter cycle

III. Oxidative Phosphorylation -- follows TCA cycle (with O₂); involves electron transport chain  
            (in cristae of mitochondria); generates ATP (similar to the light reactions of PS)
        As before, ATP formation (phosphorylation) coupled to proton (H⁺) movement -    
                Chemiosmosis
        Initial electron donor is NADH + H⁺; final electron acceptor is O₂ (last step generates water)
  Fats and Proteins can be hydrolized and utilized, entering the cellular respiratory reactions at      
           different places:

• Fats broken down into glycerol (3C) and fatty acid chains, which are further broken down 
  into 2C bits and converted to Acetyl CoA
• Proteins broken down into Amino Acids, converted into appropriately sized (# of C)
  molecules in glycolysis or the TCA cycle