Question

nadh, fadh₂, and q plug electrons into machines that run on a flow of electrons through reactions. as electrons flow through complexes i, iii, and iv, energy is released that causes the complexes to change shape, allowing protons (h⁺) to move from one side of the inner mitochondrial membrane to the other. these three complexes act as proton pumps, establishing a high concentration of h⁺ in between the two mitochondrial membranes.
in effect, the complexes are like an assembly line where electrons get passed from one position to the next. each time an electron moves, a little bit of energy is released, and that energy is used to pump protons. if one part of the assembly line stops, electrons cant move to the next position, energy stops getting released, and no more proton pumping can happen.
so what happens to the electrons once they have run through the etc? the answer lies in complex iv. in addition to pumping protons across the inner mitochondrial membrane, complex iv contains a region where oxygen molecules (o₂) from the air act as an electron acceptor. when this occurs, the double bond joining the two oxygen atoms in molecular oxygen breaks, electrons are added, protons follow the electrons, and a water molecule forms. oxygen is the last electron acceptor in the etc. it acts as the final member of the electron movement assembly line.
multiple energy transformations occur at the electron transport chain. drag and drop to match the correct type of energy transformation to both etc events listed below.
removal of electrons from nadh causes complex i to change shape.
movements of complex i cause the concentration of h⁺ to build up between membranes.
:: chemical energy to mechanical energy :: mechanical energy to electrochemical gradient
did you fully understand the

Explanation:

• When electrons are removed from NADH (a chemical process), it causes Complex I to change shape (a mechanical change). So, this is a chemical energy to mechanical energy transformation.
• The movement of Complex I (mechanical) leads to the buildup of \(H^{+}\) concentration (an electrochemical gradient). So, this is a mechanical energy to electrochemical gradient transformation.

Answer:

• Removal of electrons from NADH causes Complex I to change shape: Chemical energy to mechanical energy.
• Movements of complex I cause the concentration of \(H^{+}\) to build up between membranes: Mechanical energy to electrochemical gradient.