NEW! Mammalian Cytochrome c Oxidase Mechanism

The video tutorial explains the mechanism of cytochrome C oxidase, focusing on proton pumping and electron transfer within the mitochondria. It details how the enzyme uses protons from the mitochondrial matrix to create a proton gradient, essential for ATP synthase. The mechanism involves multiple steps of electron flow and proton transfer, ultimately converting molecular oxygen into water. The tutorial emphasizes the importance of understanding these processes for a deeper insight into cellular respiration.

What is the primary function of cytochrome C oxidase in the mitochondria?

• To produce carbon dioxide

• To synthesize glucose

• To pump protons and form water

• To break down fatty acids

How many protons are pumped into the inner membrane space by cytochrome C oxidase?

• 2 protons

• 4 protons

• 6 protons

• 8 protons

What is the role of dioxygen in the initial steps of the cytochrome C oxidase mechanism?

• It acts as a substrate for ATP synthesis

• It is reduced to form water

• It is oxidized to form carbon dioxide

• It binds to copper complexes

Which component is involved in the electron transfer from copper A to hem A?

• Tyrosine

• Histidine

• Cytochrome C

• Dioxygen

What is the significance of the tyrosyl radical in the mechanism?

• It initiates the electron transfer

• It stabilizes the copper complex

• It participates in proton transfer

• It forms a covalent bond with histidine

During the proton transfer process, what is the role of histidine?

• It deprotonates water molecules

• It stabilizes the enzyme structure

• It acts as a proton donor

• It facilitates electron transfer

How many hydronium ions are pumped from the matrix during the mechanism?

• 4 hydronium ions

• 6 hydronium ions

• 8 hydronium ions

• 10 hydronium ions

What happens to the electrons transferred from cytochrome C in the final steps?

• They reduce molecular oxygen

• They are stored in the mitochondria

• They are used to synthesize ATP

• They regenerate the enzyme's initial state

What is the final product of the cytochrome C oxidase mechanism?

• Carbon dioxide

• Oxygen

• Glucose

• Water

How is the enzyme cytochrome C oxidase regenerated at the end of the mechanism?

• By binding new substrates

• Through electron and proton transfers

• By releasing ATP

• Through a change in pH