The Queen has toured a world-leading research institute in Cambridge dubbed the "Nobel Prize factory".
Peering down a powerful microscope to look at tiny mice eggs, the Queen appeared fascinated as scientists explained their work trying to discover why some women trying to conceive produce abnormal eggs.
About 10 perfectly circular mice eggs had been readied for viewing by Dr Melina Schuh and her team from the Medical Research Council Laboratory of Molecular Biology in Cambridge.
The Queen and the Duke of Edinburgh arrived at the city by scheduled train service from London, then travelled the short distance from the station by using the guided busway service.
The couple sat apart, each with a window seat on opposite sides of the bus which arrived more than 15 minutes late, although it is not known if the train was delayed.
The visit marked the official opening by the Queen of the institute's new £212 million building which provides better facilities and equipment for the 600 scientists and support staff.
Martin Dougherty, Chief Operating Officer at the Medical Research Council Laboratory of Molecular Biology, said The Queen and the Duke of Edinburgh were very interested in the work being done at the site.
The Laboratory of Molecular Biology (LMB) has been pioneering medical breakthroughs since it was established in 1947 and researchers working at the facility have been awarded nine Nobel Prizes.
One of the most famous awards went to James Watson and Francis Crick who, with Maurice Wilkins, won the 1962 Nobel for medicine for their discovery of the structure of DNA.
The latest Nobel was won by Venki Ramakrishnan in 2009, who used x-ray crystallography to determine the structure of ribosomes - complex, bead-like structures found in cells - which translate the DNA code into life, producing the tens of thousands of different proteins that in turn control the chemistry in all living organisms.
The work shed light on how antibiotics function and will be critical in developing new antibiotics to combat infection and disease.