Mitochondria under the microscope. Microscopes have been crucial for our understanding of mitochondrial structure and function. Mitochondria are visible under the light microscope although little detail can be seen.Transmission electron microscopy (left) shows the complex internal membrane structure of mitochondria, and electron tomography (right) gives a three-dimensional view.itochondria under the microscope. Microscopes have been crucial for our understanding of mitochondrial structure and function. Mitochondria are visible under the light microscope although little detail can be seen.