Human hair grows at an average rate of 15-20 cm/year. All this growth is concentrated at the base of the hair fiber where a-keratin filaments are synthesized inside living epidermal (hair follicle) cells and assembled into rope-like structures. The fundamental structural element of a-keratin is the a-helix. Assuming that the biosynthesis of a-helical keratin chains is the rate-limiting factor in the growth of hair, calculate the rate at which new amino acid residues must be incorporated into a-keratin chains to account for the observed yearly growth of human hair.

Question

Rory Gonzales

Biology

7 July, 00:48

Human hair grows at an average rate of 15-20 cm/year. All this growth is concentrated at the base of the hair fiber where a-keratin filaments are synthesized inside living epidermal (hair follicle) cells and assembled into rope-like structures. The fundamental structural element of a-keratin is the a-helix. Assuming that the biosynthesis of a-helical keratin chains is the rate-limiting factor in the growth of hair, calculate the rate at which new amino acid residues must be incorporated into a-keratin chains to account for the observed yearly growth of human hair.

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Answers (1)

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Catherine Buckley · Answer 1

42.279 amino acid / second.

Explanation:

The growth of the human hair is calculated as follows:

15 cm can be calculated in the angstrom = 15 * 10 ⁸

20 cm = 20 x 108 Angostrom

The number of the amino acid that can be calculated in 15 x 108 Angostrom grown per second

= (3.6 x 15 x 108) / (5.4 x 365 x 24 x 60 x 60) = 31.709 amino acid per second

The number of amino acid in alpha helix of 20 x 108 Angstrom grown per second

= (3.6 x 20 x 108) / (5.4 x 365 x 24 x 60 x 60) = 42.279 amino acid per second

So, total rate is 31.709 amino acid to 42.279 amino acid per second.