Praxis II Biology

Answer: A, The molecule that is distinguished by hydrocarbon chains is a lipid. Hydrocarbon chains are long strings of carbon molecules, each of which is bound by two hydrogen molecules.

Key Takeaway: The term lipid encompasses a sizeable group of related substances including triglycerides, phospholipids, sterols, and fat-soluble vitamins. The characteristic long hydrocarbon chains give lipids their non-polar nature and thus make them insoluble in water. Certain modifications that occur in lipids such as phospholipids and fatty acids give them the dual nature of being part hydrophobic and part hydrophilic.