1.5 Lipids
A food scientist analyzes two lipid samples. Sample X is solid at room temperature, while Sample Y is liquid. Which structural difference most directly accounts for this observation?
Which of the following correctly describes why unsaturated fatty acids are described as "unsaturated"?
A triglyceride molecule is composed of which combination of subcomponents?
Fats store approximately twice the energy per gram compared to carbohydrates. Which structural feature of fats best explains this?
A marine biologist observes that Arctic seals have a thick layer of subcutaneous fat. Which two functions does this fat layer most likely serve?
Cholesterol is embedded within animal cell membranes. What is its primary function?
A researcher removes all cholesterol from an animal cell membrane and then exposes the cell to increasing temperatures. What outcome is most likely?
Which structural feature of phospholipids is directly responsible for the spontaneous formation of lipid bilayers in aqueous environments?
In the lipid bilayer of a cell membrane, the hydrophobic fatty acid tails of phospholipids face inward. Which statement best explains why this arrangement occurs?
Steroid hormones can cross cell membranes to reach intracellular receptors, whereas most large polar molecules cannot. Which property of steroids best explains this ability?
A nutritionist compares olive oil and butter. Olive oil is liquid at room temperature while butter is solid. If a chemist were to hydrogenate the olive oil (add hydrogen atoms to its fatty acid chains), what change in physical state would most likely result?
A cell biologist places a phospholipid in a nonpolar organic solvent instead of water. Which arrangement of phospholipids would most likely form?
A student claims that all lipids share an identical molecular structure. Which evidence best refutes this claim?
During a laboratory experiment, a student observes that adding a polyunsaturated fatty acid with four double bonds to a mixture of saturated fats significantly lowers the melting point of the mixture. Which explanation correctly accounts for this observation?
Which of the following correctly pairs a lipid type with its biological function?