The passage describes lipids in living organisms.
Complete the passage by writing a suitable word in each blank space.
Lipids contain the elements carbon, hydrogen and (1) ‾\underline{\quad\quad\quad\quad\quad}. Highly concentrated, lipids are composed of glycerol and (2) ‾\underline{\quad\quad\quad\quad\quad} molecules joined together.
Because lipid molecules are (3) ‾\underline{\quad\quad\quad\quad\quad} in water, they do not affect the osmotic balance of cells. The biochemical test for lipids is known as the emulsion test. In this test, the sample is first mixed with (4) ‾\underline{\quad\quad\quad\quad\quad}, and then poured into water. If lipids are present, a positive result is shown by the formation of a (5) ‾\underline{\quad\quad\quad\quad\quad} emulsion.
An important role of lipids in mammals is to act as an energy store in (6) ‾\underline{\quad\quad\quad\quad\quad} tissue. Lipids store about twice as much (7) ‾\underline{\quad\quad\quad\quad\quad} per gram as carbohydrates. In plants, lipids are stored mainly as oils inside (8) ‾\underline{\quad\quad\quad\quad\quad}. Aside from energy storage, lipids also have structural and protective roles. For example, they provide thermal insulation beneath the (9) ‾\underline{\quad\quad\quad\quad\quad}. In cell membranes, lipids form a thin barrier known as the phospholipid (10) ‾\underline{\quad\quad\quad\quad\quad}.
