How Chromosomes Govern Protein Synthesis

DNA contains genes, and genes tell your cells how to make protein.

The step in between is the production of RNA. RNA is the "middleman" between DNA and protein.

This is known as the central dogma of molecular biology. DNA to RNA to protein. In other words, DNA directs the synthesis of RNA, and RNA directs the synthesis of protein.

RNA is a nucleic acid that's similar to DNA. It has a sugar phosphate backbone, but the sugar is ribose (not deoxyribose, like DNA). It is a polymer of nucleotides, but the bases are adenine, guanine, cytosine, and uracil (not thymine, like DNA). And RNA is single-stranded (not double-stranded, like DNA).

So DNA is a string of nucleotides, RNA is a string of nucleotides, and proteins are strings of amino acids. We can rewrite the central dogma to look like this:

Essentially we're going from the language of nucleotides to the language of nucleotides, then from the language of nucleotides to the language of amino acids.

When making RNA from DNA, we're going from the language of nucleotides to the language of nucleotides. Whenever you copy something from one language to the same language, it is called a transcription. So DAN to RNA is a transcription.

If you missed class one day and borrowed a friend's notebook to copy over the notes into your notebook, that would be transcription. Same information, same language, and a few slight differences (different handwriting, maybe a different pen colour).

Producing RNA from DNA is a similar situation. Same information (how to make protein), same language (nucleotides), slight differences (RNA is single-stranded, uses uracil, etc.).

Now let's say you have a friend who lives in Russia who just HAS to have a copy of your notes. No problem. You can copy them over for your Russian friend, but what do you have to do first? Translate them. You need to translate them into a new language; Russian.

Switching from one language to a new language is a translation. And when you switch from RNA (nucleotide language) to protein (amino acid language) that's a translation.

So, we can say that RNA is transcribed from DNA, and protein is translated from RNA. Let's look at these processes in a little more detail.