[ricbritain]

I am studying Human Biology and have been given a fact that I have come across several times before but always found difficult to believe. I know I should accept it but I just find it so amazing. The fact is:

'there is approx. 2 meters of DNA in each cell'

When I imagine the size of a cell, then I imagine the nucleus of that cell it is hard to believe this can be possible. It probably is but I thought I would share it and see what folk think.

Thanks.

[kckuhns]

Well, let's see about this.

One strand of human DNA
-------------------------
46 chromosones [23 pairs]
Base pairs [bp] = 3 billion [3x10^9]
length of one bp = 3.4 Angstrom
1 Angstrom = 1x10^-10 meters

So, one strand of human DNA should be about:
(3.4) x (3x10^9) x (1x10^-10) = 1.02 meters

Yep, there you go, about a meter.

A more interesting question is, how long is ALL the DNA in a typical human being?
So, let's see....
1 human = 75 trillion cells[7.5x10^13]  (typical)

Therefore, the length of all of the DNA for one person would be about 75 trillion meters.
That's a whopping 75 billion kilometers or 46 billion miles.
Or, to better visualize, the average distance to the Sun is a mere 94 million miles.
So the DNA in a typical human being would stretch from Earth to the Sun and back,..... 245 times!

Well, that is, if my math is correct...

Kevin

[ricbritain]

What a fantastic reply! Thank you for that. That is just the kind of thing I was looking for. I had no idea of the length of a bp. The fact that you added is even more amazing than the one I questioned.

Thank you very much and well done.

[tangoblue]

so what keeps it all so small?