What is the relationship between DNA, genes, chromosomes, etc?
In: Biology
Your entire genome (or a whole cell nucleus) is the library.
Each chromosome is a cookbook. Books consist of paper (the DNA) and binding/cover (the histones). The nitrogen bases are the letters on the paper. In the language of DNA there are only four letters, A, C, G and T.
The letters combine to make words, which we call codons. In the genetic language all the words are three letters long.
Put together a string of codons(words) and you make a recipe(gene), which is the instructions for how to make something. One of the codon-words is ATG which is called the initiator codon, and it does the same job as a capital letter, which tells you a new sentence is starting. There are also three codons called terminator codons (TAA, TAG, TGA), which do the same job as a period; they tell you where a sequence ends.
The big important part of a recipe is the ingredients and how to put them together, which we call a structural gene. The other thing you find in a cookbook is *when* to use the recipe – “this is a good drink for a hot day”, “pour this over pasta or fish”, that kind of thing. Information about when to use a gene/recipe is called a regulator.
So the purpose of all that is your cells have to make proteins (insulin, titin, acetyl coenzyme A, MTOR kinase, many, many others) for you to survive, and your DNA is the ‘cookbook’ that stores how to do all that. Instructions from the cookbook are relayed to your ribosomes (kitchens), where proteins are put together. The relaying is done by messenger RNA. Each of your cells only has one copy of each cookbook so you aren’t allowed to take them out, but you can use a notebook (mRNA) to make a copy of the recipe and then take that copy to the kitchen. Amino acids are the ingredients you cook with. Transfer RNA is the kids who hang around the kitchen and help you by fetching ingredients. The metaphor just keeps on going. 🙂
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