FOAK: sisters science homework

What is keratin made of? I managed to find this:

http://wps.prenhall.com/wps/media/objects/602/616516/Media_Assets/Chapter24/Text_Images/FG24_07.JPG

But what the heck is R?

 

Keratin is a protein.

 

If I recall school biology correctly (and it's been over ten years...), R-
indicates the characteristic group of an aminoacid. Aminoacids have a
specific structure (which I don't remember any more) and the R- part of this
structure is what identifies each aminoacid as such, as the rest is
identical for all. I presume the picture just shows the general structure of
keratin rather than a specific sequence of aminoacids.

Geo

 

Ah, Burger King.

 

Correct, it's a general abbreviation in all organic chemistry,
usually when you are involved with the "functional groups" that are your
active concern and the body of the molecule doesn't make nuch difference.
The red dots appear to indicate hydrogen-bonding (attractive forces but
not a real chemical bonds) between successive coils of the helix --
preumably what helps make the helix shape, and the dashed lines are some
sort of other inter-molecular (van der Waals?) force between adjacent
helices, helping to give the overall structyre. == are double bonds and
the narrow triangles are meant to convey distance info in the bonds (the
broad end is closer to you than the pointy bit).

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