|Animation of the anatomy of a typical human cell. The view starts outside the cell, before the top half is removed to show the internal organelles. These include the nucleus, which stores the genetic information, the rough and smooth endoplasmic reticulum, which manufacture proteins and lipids respectively, the Golgi apparatus, which packages proteins to send them to where they are required, and a mitochondrion, which produces energy for the cell. The view zooms in to a close-up of a section through the cell membrane. The membrane is a bilayer of phospholipids, which have hydrophilic heads (blue) and long hydrophobic tails (grey) pointing inwards. Proteins float inside the membrane, some crossing it completely. Some of these include glycoproteins, which aid signalling and recognition between cells, ion channels, which allow ions in and out of the cell, and receptors, which carry messages from signalling compounds outside the cell to the machinery within. This clip is available without labels - see K005/0840.