Mitochondrial disease is a group of disorders caused by dysfunctional mitochondria, the organelles that generate energy for the cell.itochondrial diseases are sometimes (about 15% of the time) caused by mutations in the mitochondrial DNA that affect mitochondrial function.
1 Surface-mounted light â the finished housing is exposed, not flush with surface. 2  Chandelier. 3  Pendant light â suspended from the ceiling with a chain or pipe.  Sconce â provide up or down lights; can be used to illuminate artwork, architectural details; commonly used in hallways or as an alternative to overhead lighting.
A penlight is a small, pen-sized flashlight, often containing two AA batteries or AAA batteries. In some types the incandescent light bulb has an integral lens that focuses the light, so no reflector is built into the penlight.Others use incandescent bulbs mounted in reflectors.he light output of an incandescent lamp in a flashlight varies widely depending on the type of lamp. A miniature keychain lamp produces one or two lumens. A two D-cell flashlight using a common prefocus-style miniature lamp will produce on the order of 15 to 20 lumens of light and a beam of about 200 candlepower.