The scheme of life

Every human being is unique, but still your DNA is 99.9% the same as everybody else’s. In other words, your genetic code alone obviously doesn’t tell all. To explain the complexity of life, we need to go a step further and translate the code itself.

The genetic alphabet only has four letters: A, C, G and T. This is the foundation of all life, from bacteria to human beings. Each individual has a unique genetic code in which the sequence of the letters differs. And, of course, the number of letters: the human genome contains no fewer than 3 billion letters, while an E.Coli bacterium has 4.5 million.

From DNA to protein

A genetic alphabet needs genes: bits of DNA that contain the code for a specific protein. Proteins cause all the chemical reactions that take place in a cell so it can do its work. If you want to find out how this works in a complex organism, you need to start with protein production. At the Groningen Biomolecular Sciences and Biotechnology Institute (GBB), researchers are trying to unravel the functions of proteins in living cells. They are also looking at the characteristics of proteins that are important for the development of medicines and food products. Once you know what the function of a certain protein is, you can start to manipulate it, for example by building that piece of genetic code into a different bacterium to make it work like a factory, producing only the substance you need. This process is known as genetic modification.

But first, from DNA to amino acid!

At the Science LinX exhibition you can see how proteins are made from a different perspective. Turn the DNA code in the Ribo Wheel until you have the right letter combination for making an amino acid. Various amino acids linked together form a protein. But is it actually a DNA code that you’re turning? Look carefully at the letters on the wheel – something is not quite right!

The wheel doesn’t contain DNA code, but RNA code. This is a copy of a much longer DNA chain (the chromosome). RNA is much shorter than DNA and is thus easier to transport in the cell. The difference lies in one single base... RNA contains the base Uracil (U), instead of Thymine (T) as in DNA.

Mutations in DNA

In the cells of plants, animals and humans (so-called eukaryote cells) the DNA always remains in the cell nucleus, while the proteins outside the nucleus are made in the ribosomes using the RNA copy. Mistakes can happen when copies are made, but even a bad copy can produce the right amino acid, because often several codons have the code for the same amino acid. If you turn the wheel strategically you’ll inevitably discover this for yourself!

Mutations in proteins

Many hereditary human diseases go hand in hand with changes in bases (mutations) that cause the wrong amino acids to be built into important proteins. These proteins often lose their function or take on another function, which can cause a disease. You can also give proteins other functions that are wanted by changing the bases in the laboratory (engineering), for example to achieve greater resistance to decomposition or an improved biological function.

Francis Crick, the discoverer of the structure of DNA, summarized this as follows: ‘DNA makes RNA, RNA makes proteins, proteins make us!’

Proteins are thus at the centre of everything, and not only on the Ribo Wheel!

Links

Colophon

Special thanks to: Ynze van der Spek, Renske de Jonge, B.J. van de Laar, Ingeborg Veldman, students of the Game Design and Development programme of the Utrecht School of the Arts’ Faculty of Art, Media and Technology, the Groningen Biomolecular Sciences and Biotechnology Institute, Prof. Oscar Kuipers and Marlies Westerhof.

Please contact Science LinX if you should have been included in the acknowledgements.

Author

Renske de Jonge