the ETC and ATP synthase protein

• Each electron carrier protein contains a cofactor, a non-protein haem group that contains an iron ion.
• The iron ion in each electron carrier protein can accept and donate electrons because it can be reduced by gaining an electron and then become oxidised by donating the electron to the next electron carrier, electron carrier proteins are called oxido-reductase enzymes,
• The electron carriers also have a co-enzyme that using energy released from the electrons pumps protons from the matrix to the intermembrane space. protons accumulate in the intermembrane space and a proton gradient forms across the membrane, the proton gradient can producer a flow of protons through the channels in the atp synthase enzymes to make atp.
• ATP synthase enzymes are large and protrude from the inner membrane into the matrix. protons can pass.