how many isoprene units are in testosterone?

Question

My teacher gave us this question for homework, to determine isoprene rule in the testosterone but i have trouble doing it 

Answer 1

Not sure how your teacher is defining an isoprene unit, but testosterone is derived from cholesterol, which is derived from squalene, which contains 6 isoprene units.  In cholesterol and testosterone, some of the double bonds within the isoprene units are been reduced, but there would still be considered to be 6 IP units.  As for the isoprene rule, that generally simply states that in most naturally occurring terpenes, head to tail condensations of isoprene units will predominate, i.e. there will be no head-head or tail-tail condensations.