Figure 1.3 Cells Are Building Blocks for Life These photographs were taken with electron microscopes (see Figure 5.3) and enhanced with added color to highlight details. (A) Liposomes are tiny round bubbles known as vesicles and are made out of the same material as a cell membrane. Liposomes can be filled with drugs and used to deliver drugs to cells. (B) Two prokaryotic cells of an Enterococcus bacterium that lives in the human digestive system. Prokaryotes are unicellular organisms with genetic and biochemical material enclosed inside a single membrane. (C) A human white blood cell (lymphocyte) represents one of the many specialized cell types that make up a multicellular eukaryote. Multiple membranes within the cell-