Question: Hello Matt, I am a student from Carshalton Boys Sports College, I am eager to know: If scientists are right in saying that every living thing has cells inside their body. Cells are living. Does this mean that there are cells inside other cells? Many thanks

Matthew Tomlinson answered on 22 Nov 2013:

Every living thing is made of cells and the cells aren’t just inside, they make up the whole person/animal/plant, in fact you are made of trillions of cells. Bacteria and fungi are also cells, they are known as single celled organisms. Cells are also living, if they weren’t then we wouldn’t be living either.

You raise a really interesting point about cells being inside cells as well. At this stage of our evolution there aren’t really cells inside cells, cell growth occurs through cell division which means that one cell splits into two to make two new cells. However, we have special things inside our cells called mitochondria, these are the energy factories of our cells and they make ATP we need to do everything, like movement, in fact muscle cells are packed full of them. A billion years ago life on earth was all based on bacteria, everything was single celled, no plants or animals and some people think that two of these bacteria got together, one was swallowed by the other and the one that got taken up became what we now know as mitochondria. So in that sense, they are like cells inside cells.

I hope I have explained that well, if there’s anything you would like to know, give me a shout!