Assume a spherical mammalian cell has a diameter of 27 microns. If a polypeptide chain with alpha helical conformation has to stretch across the cell, how many amino acids should it be comprised of ?

Options

A. 180000
B. 1800
C. 27000
D. 12000

Answer

A

Explanation

No. of amino acid in one term in `alpha` helix = 3.6
Pitch length for `alpha` Helix `= 5.4 A^(@)`
`:.` The No. of Amino acid in polypeptide
`(3.6)/(5.4xx10^(-10))xx27xx10^(-6)`
`=1.8xx10^(4)` Amino acid = 18000 amino acid