This is a picture of a liposome. It has a phospholipid bilayer to accommodate hydrophilic molecules.
Since there are so many molecules that need to be transported in the body there are many, many vesicles. The ones that I am most familiar with are those that carry neurotransmitters because that is what I am currently learning about in my psychopharmacology class. In our neurons we have vesicles that take our neurotransmitters to the presynaptic part of the nerve. Once the vesicles reach the destination they push the molecules through their membrane and out into the cytoplasm or cell body (wherever they are, really).
Side note: I have six finals and five quizzes, one lab report, one essay, and one project all this week. The problem is that I can think of about a hundred things more thrilling than studying. How do you study? Any tips or suggestions that make for good studying habits?