In this video, I go through the content required for the Lipids section of the Biological Molecules unit for AQA A level Biology. I also go through a few exam questions and their mark schemes. Comment below if you have any questions. :)
01:00 = Triglycerides 04:16 = Phospholipids 06:24 = Unsaturated and saturated fatty acids 07:23= Test for lipids 08:37= Exam questions and mark schemes
for the exam (AQA) do we have to know the chemical structures of glycerol, for example, would we have to identify, by drawing, which part of the glycerol and fatty acid are lost to produce water ?
I would definitely recommend learning this because there have been questions in the past where you have had to highlight the part that is lost during condensation of glucose so they could do the same for glycerol and fatty acids ☺️.
No, three hydroxyl groups are lost from the glycerol, and the hydrogen from the carboxyl group of each fatty acid (3) are lost in order to form the three ester bonds of the triglyceride. This results in a by-product of three water molecules. ☺️
Hi - I think that might get you just the one mark. Your two suggestions imply the same thing (and are similar to the second suggestion on the marking scheme) so you wouldn't get both marks :)
Hi, unfortunately you would not get the mark :(. I think it's because if you read the text, you're supposed to figure out that cats' milk contains the lipase, as model organisms are supposed to "mimic" humans.
