Question

The electron transport chain (ETC), or respiratory chain, is linked to proton movement and ATP synthesis. Select the statements that accurately describe the electron transport chain. Choose all that apply The outer membrane of mitochondria is readily permeable to small molecules and hydrogen ions. Electron carriers are organized into four complexes of proteins and prosthetic groups. Electrons generated by the citric acid cycle in the intermembrane space enter the ETC. Electron carriers in the ETC include ubiquinone (coenzyme Q) and cytochrome c. The reactions of the ETC take place in the outer membrane of mitochondria space. Prosthetic groups, such as iron-sulfur centers, are directly involved with electron transfer.

Answer 1

The following are the accurate statements:  

1. The outer membrane of mitochondria is readily permeable to hydrogen ions and small molecules, due to the existence of the protein that is known as porin proteins.  

2. The electron carriers are arranged into four complexes of prosthetic groups and proteins. The four complexes of electron carriers are complex I, coenzyme Q, complex III (cytochrome a, b, c), and complex IV (cytochrome oxidase)

3. The electron carriers in the electron transport chain comprise cytochrome C and ubiquinone.  

4. The prosthetic groups like iron-sulfur centers are directly taking part in electron transfer. It is these Fe-S centers, which accept and then transfer electrons.