Naked Science Forum
General Science => General Science => Topic started by: andymeg on 18/12/2014 00:56:58
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My 6 year old son wanted to know if an atom and a cell were the same size. I told him cells contain lots of atoms (well molecules) so they must be bigger. He asked how many atoms are in a cell. I fudged and said it depends on the cell.....he said what about the nucleus, how many atoms in the nucleus of a cell? I have no idea. Can anyone help please? He loves big numbers so I think he's going to like the answers.....
Thanks!
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... He asked how many atoms are in a cell. I fudged and said it depends on the cell ...
Cells are mostly water , a drop of water has 1021 molecules (http://www.madsci.org/posts/archives/2000-10/971190308.Ch.r.html).
Human cells come in different sizes but they are all much smaller that a drop of water.
So I'd guesstimate 1015 atoms in a typical human cell.
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I fudged and said it depends on the cell.....he said what about the nucleus, how many atoms in the nucleus of a cell? I have no idea.
Actually that is quite correct. There is an enormous difference in the size of cells. Some cells are visible to the unaided eye.
See: http://learn.genetics.utah.edu/content/cells/scale/
http://chemistry.about.com/od/biochemistry/f/How-Many-Atoms-Are-There-In-A-Human-Cell.htm
That last pages explains that there are about 1014 atoms in a typical human cell. Another way of looking at it is that this is 100,000,000,000,000 or 100 trillion cells.
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An interesting side is that some of the largest and most complicated individual molecules are the chromosomes.
A human cell has 23 pairs or 46 total nuclear chromosomes (plus several mitochondria each containing a single chromosome).
Each chromosome consists of essentially 2 very large mirrored molecules, that are "hydrogen bonded" together, plus a few proteins. So, essentially 92 molecules in each cell determine everything about that cell, and the whole body.
There are, of course, larger molecules called polymers generally built up of repeated elements such as PVC (poly vinyl chloride) plastic, or perhaps diamonds, but they lack the complexity of a DNA strand.