Mitochondria. Coloured Scanning Electron Micro- graph (SEM) of mitochondria and rough endoplasmic reticulum in a liver cell. The internal structure of a hepatocyte or liver cell is crowded with organelles, due to the metabolic activities of the cell. Mitochondria (pink) are sectioned through to show folds or cristae; they are sites of cell respiration and store energy. Rough endoplasmic reticulum (green) forms pathways in the cell; it is studded with ribosomes (dots, sites of protein synthesis). Liver cells detoxify waste products in blood, store glycogen and synthesize proteins. Magnification: x28,000 at 6x7cm size. x36,000 at 4x5"~PORTRAIT"