Practice Questions

Mitochondrial outer membrane permeabilization releases Cytochrome c into the cytosol, where it activates the apoptosome and executioner caspases.

The electron transport chain pumps protons into the intermembrane space, building a proton-motive force (proton electrochemical gradient) that drives ATP synthase mechanically.

Cardiolipin is a double-phospholipid compound unique to the inner mitochondrial membrane that acts as an electrical insulator to block proton leakage.

Mitochondria are the powerhouses of the cell because they regenerate adenosine triphosphate (ATP) from ADP and inorganic phosphate.

Mitochondria possess independent circular DNA genomes and bacterial-like 70S ribosomes, allowing independent transcription and translation of select proteins.

The matrix is the gel-like central compartment of the mitochondrion where the Krebs cycle takes place. Stroma is found in chloroplasts.

Cristae are folds of the inner mitochondrial membrane that house the respiratory chain and ATP synthase complexes.

The sulfation of proteoglycans and proteins is a specialized maturation step carried out by sulfotransferase enzymes located in the trans-Golgi.

Rab GTPases serve as molecular tags on transport vesicles, interacting with specific tethering complexes on target membranes to ensure docking accuracy.

The Golgi has a slightly lower pH than the ER. This acidic environment increases the affinity of KDEL receptors for ER proteins, facilitating their capture into retrograde COPI vesicles.