Quick-freeze deep-etch image of an unfixed and fractured mitochondrion. The tubular cristae average 50nm in diameter. Each cristae bears a helically arranged double row of particles with the particles spaced at 12 nm along this zipper-like arrangement. The cristae themselves assume a helical shape and the zipper array remains on the outside curve of the helix. In in situ fractures the 2 enclosing membranes lie close together. Crystals of unknown composition are often found in the mitochondria. TEM taken on 2/15/88 by C. Schroeder with Zeiss 10A operating at 80kV. Neg. 40,500X. Published in J. Cell Biol. 108:2233-2240, 1989. Adapted with permission. The raw negative was scanned with an Epson Perfection V750 Pro and this high resolution image is best used for quantitative analysis. Additional information available at (http://www5.pbrc.hawaii.edu/allen/).