"Hi! I'm Gene. I have a little time before I need to get back to work, so I'd be happy to show you around my world, the chromosome.
"There are a lot of us Genes here, so it can get pretty confusing. We are kinda the brains behind the whole operation. And not just the nucleus, but the entire cell and even the entire body. Each of us Genes have only one job to do. That's to remember exactly how to construct a single protein. I, for instance, keep the blueprint for making insulin. Insulin tells your body that the glucose (sugar) levels are too high and that your cells should begin using it to make fat. A pal of mine, whose name is also Gene, and who lives on another chromosome, keeps the blueprint for making hemoglobin. Hemoglobin is the protein that carries oxygen around in your bloodstream. He's a pretty busy fella, all right. Your body needs to make hemoglobin all the time. But, me, I don't have to work every minute. Your body doesn't need insulin except right after you eat. So, I get some time off between meals. That's why I can show you around our place.
"Let me introduce you to Polly. Polly is not a Gene like me. She's not even DNA. Polly is a protein: a special protein called an enzyme. Her real name is "DNA Polymerase" but we just call her Polly."
"Gene may be the brains around here, but we enzymes sure keep everything humming along. There are a whole bunch of us enzymes, and we each have our own job and our own name. Like Gene said, my full name is DNA Polymerase. My friends call me Polly. My job is to construct an exact copy of all the chromosomes just before the cell divides. Actually, it takes a whole team to do that job, and my part is to super-glue the nucleotides together. But I get ahead of myself.
"Gene and I are made out of small pieces hooked together to make a long strand; like train cars are the small pieces that are hooked together to make a long train. I'm made out of small pieces called 'amino acids'. You'll see how proteins like me are made when you visit RayNA. In a little bit I'll show you how Gene is made, but right now, let me show you the small pieces from which Gene is created.
"Gene and the rest of the chromosomes are made from small pieces called 'nucleotides'. Here, let me show you what a nucleotide is.
"Here you can see nucleotides being made from a base, a sugar, and a P (phosphate). There are four factories like this, each making one type of nucleotide for me to use in making a new chromosome. One factory makes a nucleotide with the name 'adenine' that we just call 'A'. There are also factories for making 'thymine' ('T'), 'cytosine' ('C'), and 'guanine' ('G').
"Take a close look at A, T, C, and G.
"That's what all the Genes and all the rest of the chromosomes are made of. See the left hand end of the nucleotides? Those are sticky spots that cause the two DNA strands of a chromosome to stick together. Scientists call them 'hydrogen bonds'. And see how A and T have two sticky spots and C and G have three? That makes A and T pair up and C and G pair up.
"Let's look at part of the chromosome to see if we can find the nucleotide pieces.
"That's the famous DNA Ladder that everyone talks about! Now, can we look closer and see the nucleotides?
PHOSPHATE (P) SUGAR BASE
"Oh, there they are. See how the sugar and P (pink and yellow parts) of the nucleotides form the edges of the DNA Ladder and the bases (blue parts) form the rungs? See how the sticky spots on the bases hold the two DNA strands together? And how the sticky spots make sure that A is always across from T and C is always across from G?
"Now you can see how Gene and all the rest of the chromosomes are made from small pieces called nucleotides. Later I'll show you how I make a new chromosome, but, right now Gene is itchy to tell you more about himself and the other Genes."
DNA STRUCTURE: For Parents & Teachers
Learn more! Google:
ęCopyright, 1998-2008, Eureka ! Science, Corp.