What is the role of the cristae in mitochondria?

Cristae are infoldings of the inner membrane of mitochondria, which significantly increase the surface area available for biochemical reactions. The primary role of cristae is to facilitate ATP production through oxidative phosphorylation, a process that occurs during cellular respiration. Within the cristae, embedded proteins and enzymes are involved in the electron transport chain and ATP synthase complexes, which are essential for generating ATP from ADP and inorganic phosphate in the presence of oxygen.

The increased surface area provided by cristae is crucial because it allows for a greater number of these protein complexes to be positioned, enhancing the efficiency of ATP synthesis as electrons pass through the chain and contribute to the proton gradient used by ATP synthase. This design is fundamental to meet the energy demands of the cell, particularly in high-energy-demanding tissues such as muscle and nerve cells.

In contrast, the other options do not accurately describe the function of cristae. Energy storage typically involves molecules like glycogen or fat, protein synthesis occurs in ribosomes, and photosynthesis is a function associated with chloroplasts, not mitochondria. Thus, the role of cristae in ATP production is critical for the energy metabolism of aerobic organisms.