Final answer:
The infoldings of the mitochondria are called cristae.
Step-by-step explanation:
The infoldings of the mitochondria are called cristae. Mitochondria are oval-shaped, double membrane organelles that have their own ribosomes and DNA. Each membrane is a phospholipid bilayer embedded with proteins. The inner membrane has folds called cristae that increase surface area. The space between the two membranes is called the intermembrane space and the space inside the inner membrane is called the matrix. ATP synthesis takes place on the inner membrane.