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Measuring Size: DNA

Réka Mascher

A single human cell contains two metres of DNA

Deoxyribonucleic acid, DNA, is the carrier of the genes of every living creature and contains all inheritable information.  It is in the form of a double helix and is two nanometres wide. Every human cell, except gametes, has twenty-three pairs of chromosomes. If one unwound one single cell of this carrier of genetic information and lined it up one behind the other, it would be two metres long.1

 

Thanks to technological developments, micrometric and nanometric measurements can be made. Researchers have got to the bottom of the building blocks of life using yardsticks that can no longer be registered by the naked eye. The Human Genome Project of the 1990s had the goal of identifying all of the genes of the human genome and determining the sequence of the approximately three billion base pairs of DNA. At the end of thirteen years, scientists managed to finally map the human genome, thus paving the way for possible therapies for genetic diseases.2 The significance of this project for humankind has been compared to the landing on the moon. Since 2013, similarly important research has been done with the goal of mapping the entire human brain. If this could be done, it would be possible to investigate the causes of incurable diseases, such as Alzheimer's or epilepsy.3 Neuroscientists are dealing with the size of a neuron, that is, one brain cell, from 0.1 to 0.002 millimetres long.4

 

Physicists at CERN (the European Organization for Nuclear Research) near Geneva are going even further: they are studying the existence of fundamental particles, measured in femtometres (10-15 metres). In 2013 Peter Higgs and François Englert received the Nobel Prize in Physics for the theory of the Higgs mechanism they developed in the 1960s.5 The existence of the Higgs Boson was confirmed in the largest particle collider in the world at CERN: it has a circumference of almost twenty-seven kilometres.6 This so-called God particle is said to be responsible for the cohesion of the particles of an atom and this for the origin of mass. In other words, the existence of the world as we know it.7 The thirst for knowledge and technological progress make possible a deeper and deeper penetration into the essence of matter and thus plumb the smallest units, from which, ultimately, the biggest things come.

Bibliography

see Bibliography here ‹Measuring size: normal weight›

Illustrations

Serena Lo Presti, MKB