# Hairs

Suppose the length of the hair is affected by only the α-keratin synthesis, which is the major component. This synthesis takes place in the epithelial cells of the hair bulb. The structure of α-keratin is made up of α-helix, wherein in one revolution it is for the 3.6 amino acid residues. Each turn increases the α-helix of 5.7 Å. During the synthesis of the α-keratin per second on average 30 formed peptide bonds.

A)

What is the rate of hair growth in mm in one day?
The result round to three decimal places [mm/day]

B)

How many days will clone hair length 4.9 cm when the initial length was 3.5 mm?

Result

v =  0.41 mm/d
t =  110.9 d

#### Solution:

$v = 30/3.6 \cdot (5.7 \cdot 10^{-7}) \cdot (24 \cdot 3600) = 0.41 \ \text{ mm/d }$
$t = (10 \cdot 4.9 - 3.5)/ v = 110.9 \ \text{ d }$

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