False-colour transmission electron micrograph of Neisseria gonorrhoeae (red), the species of bacteria causing the sexually-transmitted disease gonorrhoea. The bacterium is Gram-negative, non- motile, kidney-shaped and usually found in pairs, unlike this single specimen. The blue colour surrounding the bacterium is part of the preparation technique (shadowing), which also includes extracellular blebs shed by the bacterium, clearly seen at top. Infection occurs through genital mucous membranes of either sex. Magnification: x29,000 at 6x4.5cm size.