Hi all, sorry if this has been asked before but i cant find a thread with the info I'm after. I'm doing an access course at lvl3 (AS/A2) which includes biology and I'm stuck on the following question as part of an assignment I'm to hand in next week. Q: Suggest an explanation for the fact that sex hormones get into cells while hormones such as insulin remain outside. I know this is probably a simple thing to find out but ive been trawling google for hours and ive only managed to come up with this so far as an answer to half the question: sex hormones are a type of lipid and are classed as steroid hormones. Because they are lipids they can diffuse easily through the cell membrane. can anyone help me with why protein hormones are rejected? I'm thinking that it may be along the lines of the cell does not require any protein as it already has its own or that insulin specifically, does its job from outside the cell and doesn't need to be absorbed by the cell. Unfortunately i can only find very complicated texts about this that go over my head or else simple texts that don't address the problem. any help is much appreciated.