Thinking Small Numbers: When, Where, and How Many Molecules There Are in the Cell

Abstract

The cell is the basic unit of life. Wriggling around inside the cell are molecules with various roles; when these molecules work well together, all sorts of functions emerge. Interestingly, these molecules are surprisingly small in numbers. As a result, behavior of a minority molecule can sometimes change the function of an entire cell and therefore potentially dictate the fate of an entire organism. Here, through a conversation between a high school student (16 years old) who has recently begun to take an interest in life sciences and her biology teacher (35 years old), let us learn about the “sociality” of cells formed by these many molecules.

• Student: Our bodies are made of cells of about 10 microns in size, right?

• Teacher: Right.

• Student: But cells are really small. I can’t get a real idea of what is going on at the level of individual cells.

• Teacher: I understand how you feel. In that case, why don’t we try thinking in terms of a single “factory” so you can get a more tangible sense of the phenomena in a cell?

• Student: Yes, sir. Please explain.