LIPIDS: AQA A LEVEL BIOLOGY + EXAM QUESTION RUN THROUGH

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. :)

[@AlevelBiologyHelp]

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

[@nimo2714]

Why am I only finding your channel the night before my mocks, your amazing🙏🏼 but better late than never

[@ayowolee6811]

God bless you for this 🙏🏽

[@dorinda9677]

Thank you for doing these , really appreciate this ☺️

[@lucy-om9wy]

thank you for making these videos it is so appreciated

[@nawal8790]

you're such a great help for this, thank you

[@gewty8860]

for the question at 18:26 I pur the cats are easier to look after and require less resources to maintain would that be 2 suitable suggestions?

[@AlevelBiologyHelp]

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 :)

[@gewty8860]

@@AlevelBiologyHelp ohh okay thank you :)

[@EDITS4LIFEE007]

Hi there! would I still get the mark if I said cat's milk could also have bile activated lipase? this is for the question at 17:32

[@AlevelBiologyHelp]

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.

[@EDITS4LIFEE007]

@@AlevelBiologyHelp Ahh ok great yep that makes sense thank you!

[@xenne.]

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 ?

[@AlevelBiologyHelp]

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 ☺️.

[@mjkhupe2189]

This good knowledge

[@safandsound]

Is there only one hydroxyl group lost in the formation of a triglyceride?

[@AlevelBiologyHelp]

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. ☺️

[@dyane4720]

Do we need to know by heart the structures like the diagrams?

[@AlevelBiologyHelp]

You could be asked to draw them in the exam since a similar question about carbohydrates has come up before - so yes :)

[@xenne.]

would we ever have to identify where the phosphate group joins onto the glycerol ?

[@AlevelBiologyHelp]

It's possible that they could ask that, so I would recommend learning it!

[@Lavin.]

I dont get much about the ester bonds. can someone please please help me:)