Cytochrome c oxidase

Definition

Cytochrome c oxidase is a vital enzyme in the electron transport chain, responsible for the final step of cellular respiration where it catalyzes the transfer of electrons from cytochrome c to molecular oxygen, reducing it to water. This enzyme plays a critical role in energy production, facilitating the process of oxidative phosphorylation which generates ATP, the energy currency of the cell, from the breakdown of carbohydrates.

5 Must Know Facts For Your Next Test

1. Cytochrome c oxidase is composed of multiple subunits, including two heme groups and copper centers, which are essential for its electron transfer function.
2. The activity of cytochrome c oxidase is influenced by factors such as pH, temperature, and availability of substrates like oxygen and cytochrome c.
3. It is a key regulatory point in cellular respiration, and its activity can be modulated by various inhibitors and activators, impacting overall energy production.
4. Cytochrome c oxidase has a crucial role in maintaining the electrochemical gradient across the inner mitochondrial membrane, essential for ATP synthesis.
5. Mutations or deficiencies in cytochrome c oxidase can lead to severe mitochondrial diseases due to impaired energy production in cells.

Review Questions

• How does cytochrome c oxidase contribute to ATP production during cellular respiration?
  • Cytochrome c oxidase plays a crucial role in ATP production by catalyzing the transfer of electrons from cytochrome c to oxygen in the electron transport chain. This process not only facilitates the reduction of oxygen to water but also contributes to creating a proton gradient across the inner mitochondrial membrane. The resulting electrochemical gradient is then utilized by ATP synthase to synthesize ATP from ADP and inorganic phosphate, linking electron transport directly to energy production.
• Discuss the factors that can influence the activity of cytochrome c oxidase and how these factors may affect cellular respiration.
  • The activity of cytochrome c oxidase can be influenced by various factors including pH levels, temperature, substrate availability (such as oxygen and cytochrome c), and the presence of inhibitors or activators. Changes in these factors can either enhance or inhibit the enzyme's function. For instance, a decrease in oxygen levels can lead to reduced enzyme activity, impairing electron transport and ultimately decreasing ATP production. This demonstrates how tightly regulated cytochrome c oxidase is within cellular respiration.
• Evaluate the implications of cytochrome c oxidase deficiencies on human health and metabolism.
  • Deficiencies or mutations in cytochrome c oxidase can have significant implications for human health as they lead to impaired mitochondrial function and reduced ATP production. This can result in a range of mitochondrial diseases characterized by muscle weakness, neurological disorders, and organ dysfunction due to insufficient energy supply. The severity of symptoms can vary depending on the extent of deficiency and which tissues are most affected. Understanding these implications emphasizes the importance of cytochrome c oxidase in maintaining metabolic health and energy balance within cells.

Related terms

Electron Transport Chain: A series of protein complexes located in the inner mitochondrial membrane that transfer electrons derived from nutrients to oxygen, resulting in ATP production.

Oxidative Phosphorylation:

The metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing energy which is used to form ATP.

ATP Synthase:

An enzyme that creates ATP from ADP and inorganic phosphate during oxidative phosphorylation by utilizing the proton gradient established by the electron transport chain.