Poyekhali! Yuri Gagarin & The Dawn of Space Exploration
Specialist Imaging
Aerial and Satellite
Animals
Flowers
Landscapes
Space
Food
History
Graphics and Patterns
DNA 50th Anniversary

Testimonials

An excellent colour photoraph of Donald Campbell with Bluebird K7. If I need to buy any more pictures like that, I will certainly be using Media Storehouse Ltd.
alasdair_gardiner
11th February 2010

English

Fertilisation, SEM

Fertilisation. Coloured scanning electron micrograph (SEM) of sperm (blue) attempting to penetrate a human egg (brown). Each sperm (spermatozoa) has a rounded head and a long tail with which it swims. Women usually release one egg (ovum) per month, whereas men release millions of sperm in each ejaculation. Only one of these sperm can penetrate the egg's thick outer layer (zona pellucida) and fertilise it. Fertilisation occurs when the sperm's genetic material (deoxyribonucleic acid, DNA) fuses with the egg's DNA. When this occurs the egg forms a barrier to other sperm. Magnification: x650 when printed 10 centimetres wide.. Stunning Photo Gifts From Science Photo Library