Cooked beef. Coloured scanning electron micrograph (SEM) of the surface of a piece of cooked roast beef (bought from a supermarket), showing details of the parallel muscle fibres (top), a feature of skeletal muscle. Details of striations (banding along each fibre) are evident, though a fine layer of fat, deposited on the surface during the cooking process covers much of this detail. Magnification: x20 at 6x4.5cm size.