The membrane protein bacteriorhodpsin, which contains seven transmembrane alpha helices, w...

The membrane protein bacteriorhodpsin, which contains seven transmembrane alpha helices, was attached by its N-terminal to a glass slide, and the C-terminal chemically linked to a magnetic force microscope. The microscope tip was then pulled away from the slide. As it withdraws, a helices pull out of the membrane, two at a time, as shown in the figure, giving a force-extension curve with four ‘teeth’.

a. the force required to extract the first pair of alpha helices in the example above is given by (f/ pN)= 20(x/nm) + (x/nm)2, up to an extension of 10 nm, what is the work needed to extract the first pair of helices?

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b. What would be the work in J needed to extract 1 mol of pairs of helices?