BIOL 118 Lecture Notes - Lecture 12: Endergonic Reaction, Coupling Reaction, Exergonic Reaction
25 Feb 2017
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Document Summary
Changes in the activity of specific proteins. Signal deactivation: turning off cell signals is as important as turning them on, cells have automatic and rapid mechanisms for signal deactivation, mechanisms allow the cell to remain sensitive to future hormone signals, signaling activates phosphatases. Signaling pathway cross talk (figure 11. 17: one pathway may inhibit another, one pathway may enhance another, multiple steps allow many points for cross talk, helps in regulating the signal. Two types of energy: kinetic energy. Chemical energy: potential energy of a molecule depends on position of shared electrons, weak bonds with equally shared electrons. High potential energy: strong bonds with unequally shared electrons. Chemical reactions involve energy transformation: exothermic. Can drive non spontaneous reactions with chemical energy: couple a highly exergonic reaction. Energy released: with an endergonic reaction. Requires energy to be added: chemical energy released from one reaction will drive the other reaction.
