In the mitochondria of human cells, energy is provided by the oxidation and reduction reactions of the iron ions in the cytochromes in electron transport. Identify each of the following as an oxidation or a reduction: a. Fe³⁺ + e⁻ → Fe²⁺

Verified step by step guidance

1. Identify the initial and final oxidation states of the iron ion in the reaction.
2. Note that Fe³⁺ is the initial state and Fe²⁺ is the final state.
3. Determine the change in oxidation state: Fe³⁺ (oxidation state +3) gains an electron to become Fe²⁺ (oxidation state +2).
4. Recognize that gaining electrons results in a decrease in oxidation state.
5. Conclude that the process of gaining electrons and decreasing oxidation state is a reduction.

Key Concepts

Oxidation and Reduction Reactions

Oxidation and reduction (redox) reactions are chemical processes that involve the transfer of electrons between substances. Oxidation refers to the loss of electrons, while reduction refers to the gain of electrons. These reactions are fundamental in biological systems, particularly in energy production, where they facilitate the conversion of energy stored in nutrients into usable forms.

Iron Ions in Biological Systems

Iron ions, particularly in the forms of Fe²⁺ and Fe³⁺, play a crucial role in biological systems, especially in electron transport chains. In these systems, iron-containing proteins, such as cytochromes, facilitate electron transfer, which is essential for ATP production in mitochondria. The interconversion between Fe²⁺ and Fe³⁺ is a key aspect of redox reactions in cellular respiration.

Electron Transport Chain

The electron transport chain (ETC) is a series of protein complexes located in the inner mitochondrial membrane that transfer electrons derived from nutrients. As electrons move through the chain, they release energy used to pump protons across the membrane, creating a proton gradient. This gradient drives ATP synthesis, making the ETC a vital component of aerobic respiration and energy production in cells.