Lipoproteins are relatively large, combined clumps of both protein and lipid molecules that circulate in the blood of mammals. They come in two forms, called HDL and LDL, and they act like suitcases to move cholesterol, fatty acid remnants, triglycerides, and phospholipids from one place to another through the bloodstream. (LDL recirculates lipids throughout the body, while HDL takes lipids to the liver to excrete them in feces.) Given that lipids are hydrophobic and proteins can be hydrophilic, which of the following statements is correct? (a) The lipid portion of LDL does not dissolve in the bloodstream, while the lipid portion of HDL does. (b) The protein portions of both LDL and HDL can dissolve or interact with the water molecules in the bloodstream. (c) Neither the protein nor the lipid portions of LDL molecules can interact with water molecules in the bloodstream. (d) Both the protein and the lipid portions of HDL molecules can interact with water molecules in the bloodstream. (e) none of the above

Lipoproteins are relatively large, combined clumps of both protein and lipid molecules that circulate in the blood of mammals. They come in two forms, called HDL and LDL, and they act like suitcases to move cholesterol, fatty acid remnants, triglycerides, and phospholipids from one place to another through the bloodstream. (LDL recirculates lipids throughout the body, while HDL takes lipids to the liver to excrete them in feces.) Given that lipids are hydrophobic and proteins can be hydrophilic, which of the following statements is correct? (a) The lipid portion of LDL does not dissolve in the bloodstream, while the lipid portion of HDL does. (b) The protein portions of both LDL and HDL can dissolve or interact with the water molecules in the bloodstream. (c) Neither the protein nor the lipid portions of LDL molecules can interact with water molecules in the bloodstream. (d) Both the protein and the lipid portions of HDL molecules can interact with water molecules in the bloodstream. (e) none of the above