The fledgling field of X-ray microscopy lets researchers look inside whole cells rapidly frozen to capture their actions at that very moment. Here, a yeast cell buds before dividing into two. Colors show different parts of the cell. Seeing whole cells frozen in time will help scientists observe cells' complex structures and follow how molecules move inside them. Yeasts are eukaryotic microorganisms classified in the kingdom Fungi, with 1,500 species currently described. The budding yeasts (true yeasts) are classified in the order Saccharomycetales.