4680 years
1 x .5 = .5
.5 x .5 = .25
.25 x .5 = .125
You multiplied 3 times, so 3 times 1,620 is 4,680.
The term rare amino acids is misleading in some respects. It refers to all those amino acids that are not incorporated into proteins. We already got to know some of them like ornithine or citrulline that are rather common intermediates of the basic metabolism. Roughly 220 different structures are known, most of which occur in plant cells in a free state though glutamate-, oxalate- or acetyl- derivatives can also sometimes be found.
Source: https://s10.lite.msu.edu/res/msu/botonl/b_online/e20/20e.htm
Hope this helps!
Rutherford's experiment consistent of bombardment of a gold foil by alpha particles and then measurement of the deviation of the alpha particles. The direction of deviation indicated the charge in the region of the atom.
Most of the particles passed through without deviation, indicating that most of the atom consists of empty space.
