IL-4 increases expression of class II molecules in resting B cells, turning them into more efficient APCs.

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#Unit 6. System Physiology – Plant

Complex II contains five prosthetic groups and four different protein subunits;
a. Subunits A and B extend into the matrix; they contain three 2Fe-2S centers, bound FAD, and a
binding site for the substrate, succinate
b. Subunits C and D are integral membrane proteins, contain a heme group, heme b, and a binding
site for ubiquinone,

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#Unit 6. System Physiology – Plant

Complex III, also called cytochrome bc1 complex or ubiquinone;

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#Unit 6. System Physiology – Plant

cytochrome C oxidoreductase, couples the transfer of electrons from ubiquinol (QH2) to cytochrome c with the vectorial transport of protons from the matrix to the intermembrane space.

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#Unit 6. System Physiology – Plant

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#Unit 6. System Physiology – Plant

the Q cycle, has been proposed for the passage of electrons and protons through the complex. The net equation for the redox reactions of the Q cycle is

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#Unit 6. System Physiology – Plant

Complex IV, also called cytochrome oxidase, carries electrons from cytochrome c to molecular oxygen, For every four electrons passing through this complex, the enzyme consumes four “substrate” Hfrom the matrix (N side) in converting O2 to 2H2O