You have probably heard of bacteria and viruses that cause human diseases, and you may know about how humans fight bacteria with antibiotics and how we prevent infections by both bacteria and viruses using vaccines. But bacteria and viruses have also been fighting each other for a very long time, and studying the way they fight has taught us a lot about how organisms change over time and has also led to the discovery of an extremely exciting research tool.
This battle between bacteria and viruses is about the ability to reproduce. Both bacteria and viruses reproduce by making identical copies of themselves, and the instructions for doing this are stored in their DNA.
DNA is a long molecule that is built from a combination of four smaller molecules: adenine, thymine, guanine, and cytosine (A, T, G, and C for short). The A, T, C, and G molecules can be strung together in many different orders to make a long strand. That specific combination of As, Ts, Gs, and Cs is like a code. One DNA strand on its own will not last very long in a cell, so strands pair up according to specific rules.

License information: nan
MPAA: PG
Go to source: https://kids.frontiersin.org/article/10.3389/frym.2019.00002