Combinations of Molecules
Molecules are tiny compounds of smaller atoms, which are the smallest units of matter that still act as an element, such as oxygen or carbon. DNA strands are made of long connections of different combinations of 4 molecules, which we can think of as letters or colors. For example, let’s take 2 colors: yellow and red. If you are allowed to make a string of 3 colors, let’s see how many different combinations you can make.
Let’s start with just one color: yellow. What combinations can we make? Only one, right?
The whole thing would have to be yellow since that’s the only color we have.
What if we add a second color? Let’s add red. Now, how many combinations can we make?
So all together, using yellow and red, we already have 8 different combinations we could make.
If we had 3 colors, we could make 27 combinations.
If we had 4 colors, we could make 64 combinations. Each of these combinations gives a unique instruction to the cell.
This table shows how many different orders of combinations you can make with different string lengths and different numbers of colors:
What’s really amazing is how complex these instructions can be, using only 4 different colors. If we put some of these 3-color combinations together, as if we were putting different letters together to make words, we could make even more combinations.
Let’s think again about our 4 colors that can stand for different DNA molecules… red, yellow, blue, and green. These colors could join together like colored beads in a long necklace (or strand), hundreds or thousands of beads long.
One more thing to think about when you are imagining these necklaces is that DNA actually has two strands of colors, or molecules, that are connected, with certain colors almost always sticking together. For example, red would go with yellow, and blue would go with green.
Once we have these long, double strands, we have long sections in them that we call “genes.” A gene is a section of DNA that decides what traits we will have, such as if our eyes will be blue or what color our hair is. Monster DNA might decide if they have polka-dots on their body or if they have one or two eyes or horns.