CAIE A Level Biology 9700 · Biological molecules
A student observes that oil droplets (triglycerides) form spherical droplets in water, whereas phospholipids spontaneously form a bilayer.
Compare the structures of a triglyceride and a phospholipid, and explain how the structure of a phospholipid enables it to form a bilayer in an aqueous environment.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Compare means: Give similarities or differences between two things, and say which side each point belongs to. Write each point as a pair, for example: A is X, whereas B is Y. Two separate descriptions rarely earn the marks.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.