Which of the following statements about apolipoproteins (with the possible exception of apoB-100)is TRUE?
(I)The apolipoproteins are water-soluble and loosely associate with the lipoproteins.
(II)The apolipoproteins contain helices with hydrophobic and hydrophilic groups on opposite sides of the helical cylinder.
(III)The apolipoproteins are synthesized in the intestinal tissues.
(IV)The apolipoproteins appear to float on the surface of phospholipids.

Question

Quizplus · Accepted Answer

Apolipoproteins are indeed water-soluble and can loosely associate with lipoproteins, which allows them to interact with both the aqueous environment and the lipid core of lipoproteins (I). They are structured to have amphipathic helices, meaning they have hydrophobic and hydrophilic sides, allowing them to stabilize the emulsion of lipids in water by positioning the hydrophobic side towards the lipids and the hydrophilic side towards the water (II). While some apolipoproteins are synthesized in the liver, not all are exclusively produced in intestinal tissues, making statement III not universally true for all apolipoproteins. They do indeed appear to float on the surface of phospholipids due to their amphipathic nature, which allows them to interact with the hydrophilic head groups of phospholipids and the aqueous environment (IV).

Which of the Following Statements About Apolipoproteins (With the Possible