AS Biology - Humoral immunity (OCR A Chapter 12.6)

[@sophietenbosch5498]

Could not get through bio alevel without you

[@BioRach]

Haha glad to be of help! Thanks for watching :D

[@CK-vc4lq]

I have just discovered ur channel, the day before my AS paper 2, you are literally saving my exams

[@zaynabmalik806]

Your videos are saving my a level biology tysm😫🥲❤️

[@mariamaljifri5393]

I'm so happy I found this channel you're amazing. thank you so much!

[@sabavaezshooshatri2441]

I really love the way you explain things. Would be grateful if you did some videos on aqa as well

[@BioRach]

Haha glad to hear that! The pictures do make it easier to understand certain topics :) I probably won't have time in the near future to cover the AQA spec, but as far as I know, the content should be pretty much the same. The main difference between OCR and AQA is probably the style of exam questions... So feel free to check out the videos to understand the content, then practise AQA questions and you should still be fine! :D Thanks for watching!

[@yasmin6291]

Last paper 3 exam tomorrow, thank you so much for everything !!

[@OverweightRodian]

I just want to say thank you for these videos. Just finished my a levels and these really helped me.

[@silverorange0332]

Hey Biorach, I absolutely love your videos they are so concise and easy to understand🥰. Just thought I would let you know that in the OCR A textbook it says clonal selection is to do with T helper cells binding to a B APC then causing this specific B APC to clone due to the production of interlukins instead of when the antigen binds with the B lymphocyte

[@emmadeakin1049]

your videos have saved my life. just saying

[@BioRach]

haha glad it helps with your revision! Thanks for watching :D

[@Gloxy_16]

Thanks you so much for these vodeos❤

[@libbypearson-qu2um]

legend

[@libbyharris1749]

Is clonal selection where the B cell binds to the antigen, or where the T cell binds to the B-APC? Absolutely love your videos btw :)

[@BioRach]

Glad you like the videos :D and to answer your question: technically can be both...! Antigens (either free ones or those presented by T helper cells) bind and activate pre-existing B cells that have the complementary antibody (ie. Being "selected").

[@martynakonieczka9153]

cool video!

[@FaizanA-mh4pd]

Thanks for this. I have a quick question. At 2:35 , does the t helper cell need to be complimentary to the antigen in order to release interleukin? Or does it just recognise it and not bind? Because it shows the t helper biding to the b apc. Just consider about this part. fantastic and clear video!!!

[@BioRach]

Good question! Rather than saying complementary, it's the CD4 receptors on the T helper cells that can recognise and bind to MHC, which is only present on the APC surface if they're presenting an antigen. Then this binding draws the two cells closer which causes an cascade of enzymes/proteins being activated (a complicated process which we're not covering here), ultimately leading to interleukins being released. Hope this makes more sense and thanks for watching! And I see you're a "Seven deadly sins" fan? 😉

[@FaizanA-mh4pd]

@@BioRach Who decided I am a fan? You? Who are you to decide I am a fan? On a serious note though haha, thank you very much. Very helpful! thanks again for making these videos.

[@BioRach]

Haha not a problem, thanks for watching :) just saw your profile pic and name and thought you might have liked the anime! 😂

[@FaizanA-mh4pd]

@@BioRach Noooo It was a reference from the anime 🤦‍♂️😂😂 never mind.

[@honeyimhome5433]

@@FaizanA-mh4pd I get the reference

[@abdullahalazzawi5077]

Just want to make this clear at 2:03 Does the B-APC not have an MHC complex, but instead just has an Antibody-Antigen complex?

[@BioRach]

B-APC does have MHC, which is what allows it to present the antigen on the surface, but the spec didn't make it very specific/clear... But they do have MHC :) Hope this helps and thanks for watching!

[@iffy_x]

Hi, what type of b-cell has the complimentary antigen to engulf the pathogen?

[@pavxxx7122]

2:38 so what is the role of Interleukins?

[@anialex24]

Stimulate clonal expansion

[@BioRach]

It's a specific type of cytokines that is released by T helper cells. Since they are cytokines, they signal other cells for various actions, one of which is B effector cells to undergo clonal selection and expansion. Hope this helps and thanks for watching! :)

[@pavxxx7122]

BioRach thank you! Xx

[@user-zn3um6uf9m]

is cell mediated immunity the primary immune reponse and is humoral the secondary immune response?

[@BioRach]

Not exactly. I'd say the primary immune response is inflammation, which is the non-specific response. Cell-mediated and humoral responses are both secondary.

[@arusawaseem6737]

Is this on the spec for the 2019 exams? I just had a look and it doesn't mention anything about humoral immunity

[@BioRach]

Yes the word "humoral immunity" isn't on the spec, but it is part of the specific immune response (along with cell-mediated immunity) - refer to spec point 4.1.1 (f) about clonal selection and expansion.

[@arusawaseem6737]

@@BioRach Thank You!

[@hamzaelgendy-cc8xi]

Hello do you have to learn antibody structure ???

[@BioRach]

Yes you do! Exam questions may also link this to different levels of protein structures.

[@ratatouille8542]

3:57

[@DreamWhisper]

Nice but better if its only your voice

[@BioRach]

Aisyah Ruslan haha thanks! It doesn’t sound as dry with the BGM on... I’ll definitely tune it down though!

[@SyedAli-wk7dq]

Aisyah 😅