00:00= Intro, monosaccharides and disaccharide 5:10= Structures of starch, glycogen + cellulose 11:37= Benedict's test for reducing and non-reducing sugars 14:11= Exam questions and mark schemes
thank youu this is very helpful especially the exam qs. one q , for Q3a, are the hydroxyl and hydrogen groups on carbon 1 inverted for cellulose since its alternately inverted?
Hi! Yes, I would recommend learning about branched (amylopectin) and unbranched/helical/coiled starch as the specification wants you to know the structure of starch, so learn both to be on the safe side. Although if you come across an exam question that asks you to describe how starch is adapted for its function, the mark scheme often only accepts helical/coiled. :)
How is it shown in the diagram that starch is a polymer of alpha glucose molecules, and cellulose a polymer of beta glucose molecules? Or is that just a good go-to answer for these types of questions?
Each beta glucose molecule is inverted in a polymer (cellulose) due to its structure. You can see that each beta glucose is inverted in the cellulose chain (i.e. in one molecule oxygens are 'on top' and in the next they're 'on the bottom'). Alpha glucose does not have this inversion . Hope this make sense 😃
If you look at what happened in the reaction, an OH from one glucose and a H from the other have broken off during the bond, therefore to make it balanced you need to add them back as water. It sort of breaks the brain a bit because hydrogens aren’t supposed to be shown on skeletal formula but they are specifically in some parts of glucose so it appears that more are missing than there actually are.
00:00= Intro, monosaccharides and disaccharide
5:10= Structures of starch, glycogen + cellulose
11:37= Benedict's test for reducing and non-reducing sugars
14:11= Exam questions and mark schemes
Just a tip: remember to always say Iodine SOLUTION as iodine is commonly found as a gas so you don't want to lose marks on a simple mistake :)
Very very much appreciated, especially the exam questions at the end. 😊
Thank you, glad I could help :)
best aqa a level biology teacher on youtube by farrrrrr!
Thank you!!!!!
this channel is so perfect. is there any channels like this for chemistry
Thank you! Unfortunately, no there isn't. 😭
eliot rintoul is great
Allery chemistry
Thanks pal , this is my first day in college , this helped a lot I understood a lot of it
How's college so far? Any tips as I've just started?
@@zq1921 hey same, what subjects are you taking?
@@emmdemm4433 maths bio chem, u?
@@zq1921 geog, bio chem :)
@@emmdemm4433 how you finding bio and chem so far?
thank youu this is very helpful especially the exam qs. one q , for Q3a, are the hydroxyl and hydrogen groups on carbon 1 inverted for cellulose since its alternately inverted?
Do you need to know about branched and unbranched chains in starch?
Thank you for this video btw, very helpful :)
Hi! Yes, I would recommend learning about branched (amylopectin) and unbranched/helical/coiled starch as the specification wants you to know the structure of starch, so learn both to be on the safe side. Although if you come across an exam question that asks you to describe how starch is adapted for its function, the mark scheme often only accepts helical/coiled. :)
thank you so much! please do a video on all of cells exam questions or send a link of one you have already? x
You are amazing!!! Thank you so much!!! You are helping me so much!!!
Doing this over the year 11 holidays as a transition video!!
That's great! Do enjoy your summer too, as you have a tough couple of years ahead of you :)
Hii, do you have any extra information that we can add for an A* to 25 markers?
How is it shown in the diagram that starch is a polymer of alpha glucose molecules, and cellulose a polymer of beta glucose molecules? Or is that just a good go-to answer for these types of questions?
Each beta glucose molecule is inverted in a polymer (cellulose) due to its structure. You can see that each beta glucose is inverted in the cellulose chain (i.e. in one molecule oxygens are 'on top' and in the next they're 'on the bottom'). Alpha glucose does not have this inversion . Hope this make sense 😃
Thank you soo much, this was extremely helpful
When you haven’t done any revision and you’re going into year 13 😔😔😔
There's still a lot of time! You've got this!
Does this contain everything I need to know for the spec?
@@user-sl4pw3fr2k Yes :)
Is this As because I have my As exams this June?
Yes - this is AS
Thank uuuuuiu sooooo much
You're welcome 😀
hii love this video, at 3:05, why is +H2O used? wouldn’t it not be -H2O because water is excluded during a condensation reaction?
it's showing the products of the reaction, so you have the disaccharide and one molecule of water which was removed (when the bond is formed)
If you look at what happened in the reaction, an OH from one glucose and a H from the other have broken off during the bond, therefore to make it balanced you need to add them back as water. It sort of breaks the brain a bit because hydrogens aren’t supposed to be shown on skeletal formula but they are specifically in some parts of glucose so it appears that more are missing than there actually are.
@@Jaydee-wd7wr okay, thank you so much! :)
@@FR-hk7qm okay thank you!
u forgot to mention amylose and amylopectin in the starch part... 6:53
14:45
i understand your budget might not support it, but investing in something touchscreen and a pen could make life much easier for you
Hi - I didn't have one at the time of making this video ( this was my very first one) so that's why it's a bit rubbish!! :)