Cellular respiration 3

Cellular respiration 3

1. The elctron tansport chain; the hydrogen atoms carried by reduced NAD+FAD molecules generated in the krebs cycle are the source of electrons that are passed along a series of electron carriers which form the elctron transport chain

2. Reduced NAD or FAD from Krebs

   • H+
   • 2e-
     • 2e-
       • H2O
         • 2H+
         • 1/2 O2
       • Electrons at low energy level
     • Electrons at high energy levels

3. The site of the electron transport chains and AP production; the redox reactions take place on the inner memebranes of mitrochondria in which the electron carriers are embedded. The inner membrane is highly folded into structures called cistrae which increase the surface area on which the reations take place

   • According to the chemisomotic theory each individual redox reaction releases energy, but not enough to make ATP. Instead, the energy is used to pump protons (H+) from the mitrochondrial matrix into a compartment between the inner and outer mitrochondrial membranes
     • The protons accumilate so that a steep concentraion gradient develops between the compartment and the mitochondrial matrix. The inner membrane is generally impermeable to the protons except at special structures called stalked particles which function as chemiosmotic channels. Therefore, the protons can only diffuse back into the matrix through the stalked particles. The energy associated with the flood of protons through the chemiosmotic channels drives the synthesis of ATP. The photophorylation of ADP is catalysed by an enzyme called ATPase loacted in the bulbous end of the stalked particle