Alive with Cells Lesson
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Every living thing is made up of
cells.
Our bodies have billions of them. All of these cells
are working every second
of every day to help us live. Just like humans cells die. Cells are replaced
by other cells just as we have replaced the people that came before us. Cells are so small that you need a very powerful microscope to see them. It would take 2000 red blood cells to reach across your thumb. Cells are made up of mostly water. The water is held in the cell by a thin membrane. The membrane works like a balloon does when you fill it with water. This cell membrane is so small that it would take 10,000 stacked up membranes to equal the thickness of one piece of paper. Inside the cell, a whole lot of work is taking place. Imagine a chocolate factory. Imagine all of the ingredients needed to make the chocolate. Imagine all of the machines needed to make the chocolate. Now imagine the trucks leaving the factory and delivering the chocolate so you that can eat a candy bar. The cell works just like a factory. The cell membrane is like a gate in a fence around a factory. It allows things to move in and out of the cell.
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