BIS 2A Lecture Notes - Membrane Potential, Decarboxylation, Coenzyme A
10 May 2018
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Introduction to Respiration and Electron Transport Chains
●Terminal electron acceptors: the compounds onto which the electrons are “dumped”
on
â—Źredox reactions harvest energy for the cell by coupling exergonic redox reaction to
an energy-requiring reaction in the cell
â—Źelectron transport chains: chain of redox enzymes and electron carriers
â—‹aerobic eukaryotic cells- composed of 4 multi-protein complexes in the inner
mitochondrial membrane and 2 diffusible electron carrier
â—‹creates a transmembrane electrochemical gradient
â—Źoxidative phosphorylation: process of ATP synthesis that relies on redox reactions
to create an electrochemical transmembrane potential that can be then used by the
cell to do the work of ATP synthesis
Quick Overview of Principles Relevant to Electron Transport Chains
â—ŹETC begins with addition of electrons from NADH, FADH2, and other reduced
compounds
â—‹free energy transferred from these exergonic redox reactions is coupled to
the endergonic movement of protons across a membrane
â– creates an electrochemical gradient: separation of charge and pH
gradient across the membrane
â—Źproton motive force: free energy potential with an
energetically “downhill” exergonic flow that can be coupled to
a variety of cellular processes
Electron Transport Chain Overview
â—ŹStep 1
â—‹electrons enter from an electron donor
â– entry at a specific spot depends upon the respective reduction
potentials of the electron donors and acceptors
â—ŹStep 2
â—‹after 1st redox reaction., the initial electron donor will be oxidized and the
electron acceptor will be reduced
â– deltaG gives difference in redox potential
â—ŹStep 3
â—‹if sufficient energy is transferred during an exergonic redox step, the electron
carrier may couple this negative change in free energy to the endergonic
process of transporting a proton from one side of the membrane to the other
side of the membrane
Document Summary
Terminal electron acceptors: the compounds onto which the electrons are dumped on. Redox reactions harvest energy for the cell by coupling exergonic redox reaction to an energy-requiring reaction in the cell. Electron transport chains: chain of redox enzymes and electron carriers. Aerobic eukaryotic cells- composed of 4 multi-protein complexes in the inner mitochondrial membrane and 2 diffusible electron carrier. Oxidative phosphorylation: process of atp synthesis that relies on redox reactions to create an electrochemical transmembrane potential that can be then used by the cell to do the work of atp synthesis. Quick overview of principles relevant to electron transport chains. Etc begins with addition of electrons from nadh, fadh2, and other reduced compounds. Free energy transferred from these exergonic redox reactions is coupled to the endergonic movement of protons across a membrane. Creates an electrochemical gradient: separation of charge and ph gradient across the membrane.
