False-colour transmission electron micrograph (TEM) of Neisseria gonorrhoeae (gonococcus), the species of bacteria causing the sexually- transmitted disease gonorrhoea. The bacterium is Gram- negative, non-motile, kidney-shaped and is typically found in pairs. Infection occurs through genital mucous membranes of either sex: symptoms include pain on passing urine, a discharge of pus from penis (men) & vagina (- some women experience no initial symptmoms). If untreated, infection spreads & may cause sterility (women): severe inflammation of urethra (men) may prevent passage of urine. Magnification: x25,000 at 6x4. 5cm size.