πŸ”§ Control of gene expression

While the genotype represents the genetic information contained by the totality of someone’s DNA, the phenotype represents the products from DNA and genes that actually get expressed (many genes are not expressed) to make an organism appear and function the way it does. These products are in the most obvious and tangible sense, proteins. Proteins are at the heart of biological organisation in both structure and function, and span a huge variety of types, from strong cartilage and protective keratin, to efficient digestive enzymes and oxygen-carrying haemoglobin.


The pathway between genes and proteins involves two key events, and a few more smaller steps. The key events are transcription and translation. DNA itself doesn’t get too involved in the process. It is a permanent hard copy, and cannot be subjected to the ups and downs of biology, especially in terms of regulating the processes by which proteins get made based on genetic information. Factors affecting these processes operate both inside cells and outside of them.


Therefore, a reversed copy of the relevant gene is made via messenger RNA (mRNA). This is transcription. The much more complex process of using this code to build complex proteins is translation. It assembles proteins step by step, using protein building blocks – amino acids. Each 3 consecutive mRNA bases code for 1 amino acid in a protein. Hence, the 3 bases are known as…

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