While prokaryotic cells do not have membrane-bound structures, they do have distinct cellular regions (Figure 1). In prokaryotic cells, DNA bundles together in a region called the nucleoid. Primitive ...

Most cell signals are chemical in nature. For example, prokaryotic organisms have sensors that detect nutrients and help them navigate toward food sources. In multicellular organisms, growth factors, ...

All complex life forms on Earth, including plants and animals, are made up of eukaryotic cells; they are more sophisticated than bacterial or archaeal cells, which are prokaryotic. Eukaryotes have ...

The chemical reactions on which life depends need a place to happen. That place is the cell. All the things which biology recognises as indisputably alive are either cells or conglomerations of cells ...

There are some major evolutionary jumps that seem to have occurred only once. Eukaryotic cells contain membrane-enclosed structures to perform different functions, and they comprise all forms of ...