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Understanding DNA (for kids and challenged adults!)

July
6

Cells: basics of our lives

Trillions of cells make up our body.  In one hand, you have 2.5 billion cells, and they all fit because they are so tiny!  If only we could see them.  Imagine if those 2.5 billion cells in your hand were the size of one pebble of sand from the beach:  your hand would be as big as a school bus!

Humans have a job to do, and cells do to.  Each cell has a specific job, like helping to see, or feel things through touch, or help us hear, or move the oxygen around our body, while others help to process all the food (and ice cream!) we eat.  If you were going to place a “help wanted” to fill all the jobs in your body, you would need to place more than 200 ads because there are over 200 cell types doing over 200 jobs!

How does each cell know what job they are supposed to do?  It is the same as humans, when you get a job at Burger King, the “boss” is there to tell you everything you are supposed to do.  In the body, the boss is a molecule called DNA.

Oops, I have to stop and tell you about a “Molecule” now!  A “molecule” is the smallest unit (smallest “piece”) of a substance (a “thing”) that has all the same properties of the substance.

For example, a WATER molecule is the smallest unit/piece of water that is still considered water.  If we need to divide the molecule into smaller parts, we divide them into “atoms”.  But an atom from water does not have the same properties of water.

To have water, we have to put the atoms back together until they form the water molecule!

DNA is a “book of instructions” that tell the cell what job is has been assigned.  Just like a computer has a code or language like Windows or Unix telling it what to do, our bodies have DNA.  Or, you can think of DNA as the blueprints — just like when building a house, everything gets written down and drawn on paper or “blueprints” to make sure that everyone involved with building the house knows what part of the job they are responsible for doing.

But DNA only is only four letters long!  And it is not flat like a paper or a book.  It is a curved ladder … but the ladder has a special name — a “double helix”.  Those four letters that make up the DNA alphabet are called “bases”, and they are like the “rungs” or steps of the ladder, while sugars and other “atoms” make up the handrails.

Each of the steps or “rungs” of the ladder are special and each has a name.  However, just like people, they prefer to be called by their initials or “nickname”:  “A”, “T”, “C” and “G”.  They also don’t like to be alone, so they always pair up with a friend — but they are very particular as to which friend they will hook up with.

A and T are best friends and always hang out together
G and C are best friends and always hang out together

Do you like jigsaw puzzles and making the pieces fit together?  Think of A, T, G and C as jigsaw pieces.  A and T fit together; and C and G fit together.  Just like you can’t put pieces of a jigsaw puzzle together if they don’t fit — the same is true here, you can’t put the wrong friends together!


The Four Letter Alphabet:

Think about the words you can spell and the letters in those words.  We can put the letters together to spell many different words (like CAT, can be ACT; WATERMELON, can be WATERLEMON, and OWNER METAL).  Sometimes when making new words we leave letters out, or repeat the same letter, but we always have the same group of letters no matter what!

As you can see, depending on how we put the letters together, we can make new words.  The same is true in the four letter alphabet of DNA!

Each of these letters get together in groups of three.  The scientists call this a “codon”.  The “words” are put together to form a sentence; these sentences are called “genes”.

Each sentence instructs a cell to make a special molecule that is known as a “protein”.  Proteins control everything in cells.

Another way to think about it … DNA is like the “boss” of the company.  The boss issues instructions, but never does much heavy lifting!  The proteins however, provide the help necessary for each cell to do its job.  Each of these genes can only make ONE protein.

If you were to play with your lego toys, and attempt to build a tower using ONLY four colors, imagine how many combinations of colors you could make?  This is the same way DNA can store so much information with only four letters.  The sequence of letters (or in our example, colors) that stores the information.

 

NOTE:  I listed this as an article for kids and “challenged adults” because I am one of those “challenged adults” that could never wrap my head around dna.  I had to bring it down to the level of a child before I could understand it.  I view it the same way as learning a language – I tell people to speak to me in the new language as if they were speaking to a child, and that helps me to grasp the words and understand the meaning.

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