Professor Alice Roberts talks bacteriophages: viruses that infect the bacteria that infect us. With the rise of antibiotic resistance they are a potential weapon against infection. We hear from Paul Hebert, the biologist behind the International Barcode of Life project – a global effort to classify the entire world’s species according to their DNA. Bristol researchers have discovered that it is more than scent and colour that draws a bee to a flower – there is also an electric field. Claire Turner from the Open University shows us the instrument she uses to detect disease. It can sense when a heart transplant patient is rejecting their new organ, purely through monitoring their breath.