At a microscopic level, we are all composed of cells. Look at yourself in a mirror -- what you see is about 10 trillion cells divided into about 200 different types. Our muscles are made of muscle cells, our livers of liver cells, and there are even very specialized types of cells that make the enamel for our teeth or the clear lenses in our eyes!
If you want to understand how your body works, you need to understand cells. Everything from reproduction to infections to repairing a broken bone happens down at the cellular level. If you want to understand new frontiers like biotechnology and genetic engineering, you need to understand cells as well (Sobel).
Your body is made of about 10 trillion cells. The largest human cells are about the diameter of a human hair, but most human cells are smaller -- perhaps one-tenth of the diameter of a human hair.
Run your fingers through your hair now and look at a single strand. It is not very thick -- maybe 100 microns in diameter (a micron is a millionth of a meter, so 100 microns is a tenth of a millimeter). A typical human cell might be one-tenth of the diameter of your hair (10 microns). Look down at your little toe -- it might represent 2 or 3 billion cells or so, depending on how big you are. Imagine a whole house filled with baby peas. If the house is your little toe, the peas are the cells. That's a lot of cells (Kolata, Eichenwald).
Anyone who reads the paper or any of the scientific magazines (Scientific American, Discover, and Popular Science) is aware that genes are BIG news these days. Here are some of the terms you commonly see: (Sobel)
- Biotechnology
- Gene splicing
- Human genome
- Genetic engineering
- Recombinant DNA
- Genetic diseases
- Gene therapy
- DNA mutations
- DNA fingerprinting or DNA profiling............
