Figure 1.

Montage transmission electron micrograph of a human sperm cell. The cell has a compact nucleus, conspicuous mitochondria, no endoplasmic reticulum, minimal cytoplasm and a large tail (about 45 μm in length). Superfluous cytoplasm and associated machinery is jettisoned when the sperm emerges from the testis, leaving a 'stripped down', minimalist cell.

Barratt et al. Journal of Biology 2009 8:63   doi:10.1186/jbiol167
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