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Science communication is important in today's technologically advanced society. A good part of the adult community is not science saavy and lacks the background to make sense of rapidly changing technology. My blog attempts to help by publishing articles of general interest in an easy to read and understand format without using mathematics. I also give free lectures in community events - you can arrange these by writing to me.

Friday, 12 August 2011

You have enough DNA to circle the Earth 4 million times!!

Unbelievable - each of us has enough DNA to circle the Earth 4 million times.

This is how it works:

If stretched, DNA in a single cell will extend to 1.5 metres**

A cell is typically 10 microns (1 micron = 10-6 m) across
Volume of a cell is of the order of 10-15 m3

Consider a 100 kg man with density equal to that of water (1000 kg/m3)
Volume of the person is 0.1 m3 (volume = mass/density)

Therefore, there are 1014 cells - this is 100,000 billion cells and
the length of the DNA is 150 billion km

This is sufficient to circle the Earth 4 million times!

** Human Genome Project has mapped 3 billion base-pairs in a human DNA. If base-pairs are 0.5 nm apart then the stretched DNA would be 1.5 m long.
Earth's circumference is about 40,000 km