Carbs and Lipids Practice Exercises: Answer Key

Q1

Q2

Q3

After exhaustive methylation and hydrolysis, a polysaccharide yielded equimolar amounts of 2,3,4-tri-O-methylglucose and 2,3,6-tri-O-methylglucose. The polysaccharide has one reducing terminus. Draw the structure of the polysaccharide.

Q4

Draw the structure of a phosphoacylglycerol that contains glycerol, oleic acid, stearic acid, and choline.

Q5

Which is more hydrophilic, cholesterol or phospholipids? Defend your answer.

Phospholipids would be more hydrophilic due to its less bulkier structure and the presence of more polar/charged groups like phosphate and choline/serine/ethanolamine.

In contrast, the only polar group in cholesterol is one hydroxyl group. When compared to the size of the molecule which is largely made of cyclic hydrocarbons, this polar group would be masked by the larger groups, making a cholesterol a more hydrophobic molecule.