Digestion and Absorption for A-level Biology: Carbohydrates, proteins and lipids (micelles)

[@MissEstruchBiology]

Hello, I hope this video helps you understand this challenging topic😊 For more STUDY TIPS and biology help, follow me on Instagram @MissEstruchBiology instagram.com/missestruchbiology/?hl=en OR if you want to get your hands on some A-level NOTES READY MADE by me with key marking points, keywords, and essay links, make your way to missestruch.com/ (this will be available from July 2021 - Can't wait?? email [e-mail] to get your hands on a copy before then).

[@aarizmushtaq4301]

Cheesecake

[@MasterArmedforces]

Hi Miss, Ive recently started eating pumpkin seeds to address low magnesium levels but I notice seed shell particles in my poop. Has the digestive process extracted the magnesium anyway, or am I losing some? In addition, will chewing gum after a meal (producing extra saliva) assist digestion in general? Thanks

[@beracahumoru5199]

Thanks 😊 🫂 miss estruch, you're so a life saver

[@raegardens8339]

Here for my mock! Hoping for good results

[@MissEstruchBiology]

Best of luck!

[@lucyhabin2609]

I have my Biology Mock A level tomorrow and this is so helpful thankyou!!

[@MissEstruchBiology]

Good luck 🤞 Glad the video has helped you prepare 😊

[@juliaonyebuchi6592]

this was so helps full I've got my 1st year 13 biology assessment tomorrow

[@MissEstruchBiology]

Good luck !!!

[@hoorias4842]

how you doing now? what course are you studying at uni?

[@UKINFLUENCERS..2881]

Hi, how're you doing now??!!

[@aminatsekoni1036]

Me toooo😭😭😭🥲🥲🥲

[@godgod6335]

Thank you miss, this channel is like a golden mine if knowledge

[@MissEstruchBiology]

Aww thank you ☺ I hope the videos are helping with your studies.

[@godgod6335]

@@MissEstruchBiology obviously miss got an A in biology thanks to you

[@jubzislam9764]

wish I came across your channel sooner! thank you and I appreciate your hard work!

[@MissEstruchBiology]

you're welcome 😊 Really hope the channel helps with your studies!

[@emmagilmartin4127]

You have helped so much! the book can only go a certain length for my knowledge! deffo using you again!! Thank YOU!!! keep it up :)

[@MissEstruchBiology]

Aww thanks Emma. I'm so pleased you are finding the videos helpful 😀

[@simdicool5438]

This was SOOO helpful, everything was in it and so well explained. Thanks!

[@MissEstruchBiology]

Thank you so much 😊😊☺ Really hope it helps with your studies

[@joeldilylez]

Wow!! Really amazing , thanks for such a plethora work madam

[@AG-ql1sy]

hello miss, im a little confused on this one, the diagram on 10:21 at the top of the page suggests that the products of lipid digestion (monoglycerides and fatty acid) are emulsified into micelles, which makes sense because it forms the micelles which can be absorbed into the epithelial cell. However at the same time i believe you said emulsification/bile salt occurs before the lipase action/ lipid digestion to provide a larger surface area and faster hydrolysis by the lipase enzyme so does emulsification happen twice? first emulsification before chemical digestion so that triglycerides are covered in bile salt to become small droplets/vesicles of triglycerides (easier to become hydrolysed) and second emulsification after chemical digestion to make the products (monoglycerides and fatty acids and bile salt) into micelles too? and so what stage are the micelles formed? are they formed twice? (lipid --> small micelle lipid droplets to be hydrolysed) and (monoglycerides and fatty acids --> small micelle droplets with bile salt, monoglyceride and fatty acids) hope my question makes sense, sorry its so wordy!

[@AG-ql1sy]

so i just had a thought, the first stage is the physical digestion where lipid + bile salt --> lipid miselles . then these same lipid miselles are hydrolysed into monoglyceride + fatty acid miselles...? hopefully you are able to clear all this up :D

[@Base_111]

lol man got blanked... but on a serious note, did you find out the answer because i was wondering the exact same as you lmao, thats y i came to the comments section

[@serenity.777]

Correct me if I’m wrong but I’m pretty sure the bile salts emulsify lipids just into smaller lipid droplets (not micelles) so larger surface area etc. They form micelles after being broken down by lipases. Also, micelles contain the bile salts and fatty acids & monoglycerides.🙏🏾

[@ayeshamahmood3342]

Thank you!!

[@MissEstruchBiology]

You're welcome! I hope it helped you ☺

[@shahzarbukhlaw5963]

Why does lipase only break down into monoglycerides and fatty acids? Why not glycerol + 3 fatty acids? Also, does this same concept apply to phospholipids?

[@alicemidori8087]

If you're asked for the products of lipase hyrdolysing triglycerides, would you just say fatty acids and monoglycerides, or include a glycerol molecule too?

[@dno.16]

Thank you

[@MissEstruchBiology]

You're welcome 😊 Hope it helped

[@UmarRashid-j4c]

Thank you so much, very helpful!

[@MissEstruchBiology]

Glad it was helpful!

[@princess-zw6rw]

doing my bedtime video watching after revising lol. end of yr 12 exam tomorrow ill try remembering to come back n update

[@MissEstruchBiology]

Good luck!!

[@lj212]

So helpful !😊

[@MissEstruchBiology]

Glad it was helpful!😀

[@liamjones496]

how are you doing now

[@demiwragility]

thanks

[@MissEstruchBiology]

You're welcome 😊

[@0x1_chips]

Do we need to know all the details on the diagram at 11:00 or is it just the text on the left side of the slide that we need to know?

[@MissEstruchBiology]

Hello, Yes, you need to know the information in the diagram also. Hope that helps :D

[@0x1_chips]

Thank you!

[@karviahamilton689]

Wonderful explanation. Thank you

[@MissEstruchBiology]

You're so welcome ☺️

[@rosemarymuchenje988]

Well explained.This was helpful.

[@MissEstruchBiology]

So glad it helped 😊

[@caitlinweir2610]

great video this helped loads thanksa bunch

[@MissEstruchBiology]

So pleased you found it helpful!!! 😀

[@elwhsijev]

Got my bio a level exchange exam today 😅

[@MissEstruchBiology]

Good luck!

[@ia8090]

thank you for the video miss. One question: why does the lipase digest the lipids into monoglycerides and not glycerol directly?

[@MissEstruchBiology]

Good question, I'm not 100% sure. I would imagine it is linked to the fact that the enzyme active site is only complementary in shape to hydrolyse one bond. It may also be that monoglycerides are small enough to be absorbed so there is no advantage to hydrolyse further.

[@oliviaglanville8472]

Do we need to know about the parts of the digestive system and their functions?

[@MissEstruchBiology]

No, the digestive system was removed from the specification when it changed in 2015. Instead, you just need to know the process of digestion and absorption.

[@emilywiggan8279]

Do u have a co transport video?

[@MissEstruchBiology]

Yes! In the topic 2 playlist

[@ell6311]

Hey, do you know what the adaptations be for absorption just because I always confuse it with gas exchange Thank you

[@MissEstruchBiology]

It is the same idea as it is adaptations for diffusion, but also active transport. So again, large surface area (many villi and microvilli and their shape) Short diffusion distance (think walls of villi and capillaries close by) Many mitochondria in microvilli for active transport. Hope that helps.

[@ell6311]

@@MissEstruchBiology thank you sm

[@mohid0786]

What's the difference between Endopeptidases & dipeptidases?

[@h1bah30]

dipeptidases break down Dipeptides (two amino acids joined together) into 2 separate amino acids whereas endopeptidases break chains into smaller polypeptides (so still more than 2 amino acids) by breaking central peptide bonds

[@ImranAwan-n9s]

Are we meant to know about chylomicrons?

[@MissEstruchBiology]

You can discuss these, but often it's not essential on a mark scheme

[@kirstengafney5100]

Does the amylase hydrolyse the polysaccharides glycosidic bonds so that it becomes a disaccharide? Thank you so much!

[@MissEstruchBiology]

Hello, Yes it does. It hydrolyses starch into maltose.

[@kirstengafney5100]

@@MissEstruchBiology Thank you so much!

[@alexisabraham3704]

Hi , have you got any revision tips?

[@MissEstruchBiology]

So many! Check out my study tips playlist 😁

[@Ella-um3su]

hi miss, the aqa spec mentions visking tubes please could you go through this?

[@gamingspotlight6194]

So why is it that carnivores have gall bladders but herbivores don’t ? I know the answer but I don’t know how to word it at all

[@MissEstruchBiology]

Try it, type what you think and I'll give you feedback.

[@gamingspotlight6194]

@@MissEstruchBiology bile is stored in the gall bladder and emulsifies lipids. carnivores diets are high in fat so need to emulsify lipids whereas herbivores diets don’t contain fat so bile isn’t needed

[@MissEstruchBiology]

That's what I would say!

[@hongjoongswife9672]

Does emulsification happen twice, ( before lipase action) and before the diffusion of the miscelles into the epithelial cells ?

[@alaynahurooj1995]

I’m not sure but even if it was to happen twice for exams itd be safe to just write about lipase action first alone and then talk about bile and how it further increases the surface area for lipase to work on.

[@toxins5803]

Do we need to know the names of any endopeptidases?

[@MissEstruchBiology]

nope not for AQA 😊

[@toxins5803]

@@MissEstruchBiology Thank you!

[@samielsir]

we do for WJEC 😭

[@_AdamFay3]

Would Maltase also be with sucrase and lactase

[@MissEstruchBiology]

Those three are all examples of membrane-bound disaccharidases

[@jayansaini7093]

Boring af

[@alexisabraham3704]

Don't be mean

[@princess-zw6rw]

why should it be interesting?? we all take a level biology so we can do something fun in uni, lol