This photomicrograph shows Micrasterias, a type of green alga called a Desmid. Desmids usually inhabit the acidic waters associated with sphagnum (peat) bogs. These particular Desmids are flat, plate-like single cells made up of two halves, which are mirror images of each other. Each half (hemicell) contains a single chloroplast – the site of photosynthesis – and the nucleus occupies the centre of the cell where the two halves join.
Micrasterias can reproduce asexually by binary fission (resulting in two separate cells, each of which has one of the parent’s hemicells and one new hemicell); however, Micrasterias can also reproduce sexually, by a process known as conjugation, which involves the transfer of genetic material between two cells.
The 12th Wellcome Image Awards were announced on 20 June 2012, recognising the creators of the most informative, striking and technically excellent images among recent acquisitions to Wellcome Images, as chosen by a panel of judges.
Image credit: Spike Walker | Wellcome Images