Stem cells function as a source of new cells to grow or replace specialised tissues. To perform this function, these cells must divide to renew themselves, while some of their descendants ...

Stem and leaf diagrams are formed by splitting the number into two parts, the ‘stem’ and the ‘leaf. For example: In the number 36, the tens would form the stem and the units the leaf.

Mammalian epithelial cells also turn over regularly, typically every few days. Whenever stem cells are called upon to generate a particular type of cell, they undergo an asymmetric cell division.

Schematic diagram showing different types of stem cells grown in microgravity (µG) on the International Space Station (ISS) and their return to Earth (1 G) for potential clinical applications.