What is the Chemistry behind "good" and "bad" cholesterol & their relation to Cis/Trans fatty acids?

I have searched Google for this but cannot seem to find an explanation. My question is as follows - what is the Chemistry/Biochemistry behind cis and trans fatty acids resulting in "Bad" LDL and "Good" HDL cholesterol? Is one synthesised favourably with cis/trans fatty acids as precursors? 


I am under the impression that LDL results in reduced cell permeability (how?), but other than that I am struggling to find information.


