Daily Live 28th May Immunity

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[00:00:10]I think I think this Instagram um those of you that can already see me in the live and Tik Tok you can go questions going to be unity based There we go. That should be going through.

[00:00:39]Live as well.

[00:00:42]Should be here any minute.

[00:00:45]Oh, right. The heat everyone.

[00:00:49]Doing revision. It is this hot. So, good going for everyone that is still going strong with their revision. Someone say [snorts] my mic is still doing that thing again. I think it must just be Oh, there we go. I'll move that down a bit.

[00:01:04]I think it must heat.

[00:01:06]And by that I mean because first of all I'm talking a lot quieter. I've got all the doors and windows open.

[00:01:16]Um but Oh, um, okay. What about now? Is the mic any better? Cuz I think you're saying it's cut out, but I think it's actually I've just stopped talking. I think maybe that's what the issue is that when I stop talking, everyone thinks I've um the mic's cut out, but actually I just stopped. See what people are saying if it is. any better on Instagram. I can't I'm just going to have to hope for the best. Okay. Right.

[00:02:08]So, um yeah, everyone's saying maybe I was just moving my mouth going ah because I'm so hot and flustered at the moment. I don't know if everyone else is, but we are going through things for um immunity today. So, we're going through some immunity questions. This is live on Instagram, YouTube, and Tik Tok simultaneously. It has only just started. It's Alevel Biology immunity questions. Um and it is recorded. This recording is available on YouTube for everyone.

[00:02:43]And tomorrow um is the pick a mix lesson. So if you need help with the paper one AQA required practicals, come along to the pick a mix lesson that is tomorrow. And that is going to be covering all of the practicals most likely to up one going through key marking points and common questions, things like that. So I'm just going to paste in the link. If you haven't signed up yet, you've still got time to come and join that class.

[00:03:16]It's at 10:00 a.m. tomorrow morning.

[00:03:20]Right, let's jump into these questions then. So, we have got going wrong now. Pen's not responding to me. Quickly just plug it in. Plug it out. It's almost like it's not just me that's tired and flustered from the heat. Also, my uh equipment is like can't deal with it being so hot. I think the first question is describe two structural features found in all viruses and for each feature state the function.

[00:03:54]Let me plug that back in so you can see it. And I better hope that my pen works and if it doesn't then I'll have to just um read out answers to you. We'll make it work somehow.

[00:04:05]Right. So there's the questions. Let's I hope now working. Woohoo! Yeah, there we go. Just simple plugin like the turning on and off again of an Apple Pen. So, the different things that you could have for this question. Oh, I can see some good answers coming in. I see some people have said capsid.

[00:04:26]The capsid is the protein coat. So if I actually just draw what you always have have the genetic material that is surrounded by a capsid then you get attachment proteins as well.

[00:04:42]Those are the three features and I've just realized that my face is covering that so you can't see it. There we go.

[00:04:48]So that was my drawing just there. They capsid the function of the capsid then so I'm going to add in the function for that is it protects that genetic information genetic material and then feature two I'm going to go for is the genetic material the genetic material the function of that is it codes viral protein.

[00:05:24]Now, you could have gone for attachment proteins as well. So, I'll add that down here. So, attachment proteins, those are what the virus bind to receptors on the host cell surface. Then insert it genetic material and replicate inside of the cell. and say bind to receptors on post cell.

[00:05:50]Okay, answers are looking good. I can see some really good answers there on um all of the different platforms. So, well done. Next then we've got describe why a virus is described as non-living and a cellular. So why is it described as um non-living a cellular camera with my face and make my face smaller cuz we don't need my face that big important that you can see question.

[00:06:26]Okay. So give one reason why it's described as cellular. Sorry, I added in the non-living cuz it said non-living there. But they just want to know why is it described as a cellular. So ascellular just means it's not made of cells.

[00:06:45]Not made of cells. But you could say for that that also means there's no cell membrane. There's no cytoplasm. It hasn't got any organels. You could have those as well. The non-living bit would be the Mrs. Gren from year seven. That's like all the things that you can break down to work out if something is a living thing. Um, so M is the metabolism. The R is I think is respiration teach so I don't remember.

[00:07:15]Um, you've then got things like can it reproduce? Can it move? Can it um like take in nutrition somehow? So you could have any of those for the non-living. a lot they've asked that but I'm just going to say no metabolism right and then give one reason why antibiotics are not effective against viruses now this is a really common question we're on this one a really common question that Alevel students get wrong because they write a GCSE answer I can actually see the answers coming in I'm looking at Tik Tok at the moment, but also on YouTube are really good. The last time I did a question like this on the lives, those people got it wrong.

[00:08:02]So, your revision is paying off. You are giving me much better answers here because the key thing is they don't have a cell wall or a murine cell wall or a pepidoglycen cell wall or ribosomes. But let me emphasize this. Oh, let me write it in.

[00:08:20]Have no cell wall.

[00:08:25]A question very similar to this came up.

[00:08:27]I think it was last year or the year before, but it was one of the papers when I was actually marking it and we were not allowed to give students the mark if they said um do not have urine cell wall.

[00:08:48]And the reason we weren't allowed to give that was AQA said that that implies you thought that a virus does have a cell wall, not one made of murine. So if you wrote that, didn't get the mark. Had to say it does not contain a cell wall.

[00:09:04]Or you could say it doesn't contain murine because it doesn't have a cell wall. But you have to make sure that you have explicitly said no cell wall and it couldn't be interpreted in any other particular way because that's the exam is okay let's go on question two HIV is a retrovirus in the chat what does it mean if it's a retrovirus what does a retrovirus mean I've thrown in an extra question there what is a retrovirus us.

[00:09:40]Yeah, good. So, retrovirus is um a virus that has RNA as its genetic material instead of DNA. So, it has RNA and therefore also reverse transcriptise.

[00:09:52]What's an example of a retrovirus?

[00:09:57]So, what is an example of a retrovirus then? If retroviruses have RNA as their genetic material, HIV. Yeah, brilliant.

[00:10:06]HIV.

[00:10:08]Um, so HIV. Oh, [laughter] also I've just realized, what's an example? It literally says it there. I told you I'm tired. This heat is really getting to me and my brain's not working. The answer was literally right there, but maybe you didn't notice that either. Um, right.

[00:10:21]HIV is a retrovirus that infects helper tea cells in the human immune system.

[00:10:26]Name the enzyme found inside of HIV that is essential for its replication and describe the role. Now, we've actually partly answered this already because we did just say um what it's a retrovirus.

[00:10:41]It's a virus has RNA as it genetic material and the enzyme reverse transcriptise.

[00:10:47]So, that is the name of the enzyme reverse transcriptise.

[00:10:57]Then we have to say what does reverse transcriptise do?

[00:11:03]I've seen some good answers coming in here.

[00:11:06]Converting RNA into viral DNA. Yeah, good. Makes a complimentary strand from the viral DNA. If you're going to say that, make sure you say complimentary DNA strand because that's the key thing that we need um that we're going to say I'm going to say it creates we could say so creates a complimementary DNA strand from viral RNA. Okay.

[00:11:43]Okay. Then which of the following best describes the genetic material carried inside of an HIV particle? Oo. Again, I've kind of given this but not completely. So, let's see what we reckon. Got double stranded DNA, single stranded RNA, double stranded RNA, and single stranded RNA. I can see most people are saying B which is the single stranded RNA which is correct. Yeah.

[00:12:15]Then for four marks the big one describe the sequence of events by which HIV replicates once inside the T helper cell. So it's already once it's inside.

[00:12:28]So we don't need to talk about binding of the attachment proteins to those CD4 receptors on the T- helpper cells. We need to say that um what happens after that point?

[00:12:52]Yes, there's some some questions coming in. This is Alevel and they're normally about half an hour. It's however long it takes me to finish these questions with you, which is typically about half an hour. Oh, I forgot to say as well that um you can actually sign up to get these questions for free. Let me find the link because if you sign up um where's my weekly live link? I go live at the moment I'm going live every day but every Thursday I go live at 8:00 p.m.

[00:13:24]even when it's not exam season and I email you the exam questions. though the link if you want to sign up I'm emailing the exam questions again at half8 you get the questions and the answers it's completely for free the link is just sent in the chat basically miss.co/weekly lives you just fill in your email and then I email you the exam questions every week um okay so that little chitchat gave people enough time hopefully answer that four mark question so let me just get that four mark um up so I can now see and answer it myself. So describe the sequence of events by which HIV replicates once inside. So we're starting from that point. But so I'm going to say already inside of the cell. So the first thing I'm then going to say is that the reverse transcriptise reverse transcriptise converts the viral RNA into DNA.

[00:14:35]Then that viral DNA can be inserted into the host's DNA.

[00:14:42]So the viral DNA is inserted into host DNA.

[00:14:57]Now that viral DNA is actually inserted into the host DNA. That viral DNA will get transcribed to make viral mRNA.

[00:15:07]Going to say host cell will transcribe viral DNA to viral mRNA.

[00:15:22]And then once we've got the viral mRNA, that means that um new viral proteins will be made.

[00:15:33]New viral proteins are made.

[00:15:39]That then means virus particle can assemble and that therefore means it has replicated. You could actually also add in I can see some really good answers coming in in the chat. People have also said that means the new virus particles can then be released from the cell which you can have. It's a four marker though and I've already got five points so I stopped there. Um but you can Oh yeah, this is Alevel. Some GCSE students like oh my gosh I thought this was GCSE and it scared me. It's Alevel. Do not panic.

[00:16:08]It is A-level. Another question. Can you say viral components? I think I've only ever seen on the mark scheme that they said the virus particles.

[00:16:18]Oh no, Tik Tok. It just ended. Why did Tik Tok shut me down again? Are we 15 minutes in some reason? Tik Tok, this keeps happening.

[00:16:28]Do not know why. Hopefully people on Tik Tok come and find me over on Instagram or on um YouTube instead. That's bizarre. Why doing that? Still haven't worked it out. If anyone knows, can they send me a message? Cuz I don't think I said anything inappropriate to get shut down. It always seems to be 15 minutes.

[00:16:45]So strange going on there. Okay, next one. Question three. Explain how HIV leads to a reduced ability to produce antibodies um as AIDS develops.

[00:17:00]So I would say for this one that HIV infects and therefore destroys help tea cells.

[00:17:21]Um, someone said your video on immunity had slightly different wording for HIV replication. Can you just type in what that wording was and I'll clarify.

[00:17:34]Um then oh I wonder if HIV so much that's why Tik Tok shut down HIV I don't know who knows Tik Tok shut me down again. They all really don't like biology do they? What is going on? Um so that's the next the first bit. Then we've got um if those tea helper cells have been destroyed that means they can't be there. So fewer say no or fewer the helper cells.

[00:18:05]So fewer or in fact I'm say that no so no B cell activation if we don't have B cell activation.

[00:18:17]So no plasma cells make antibodies and uh so no plasma cells make antibodies and no memory B cells. Okay. So that is the um answer to question three.

[00:18:45]Well 3a. Now let's go on to 3B. So scientists developed a monoconal antibbody treatment that blocks the CCR5 receptor on the T- helpper cells and that prevents HIV from attaching. they carried out a clinical trial this um and then they carried out a clinical trial comparing this treatment with a placebo in HIV positive patients over 24 months. So the results are below. So, we've got mean T- helpper cell count at the start of cells.

[00:19:28]Mean T- helpper cell count at 24 months.

[00:19:32]Patients with T- hel count of less than 200 patients reporting adverse side effects.

[00:19:39]Got our numbers here. Monoconal antibbody group and our sample size is only 20 telling us there. um placebo sample size is also um 20. We've got that AIDS symptoms typically occur when the T- health cell count falls below 200 cells per millimeter cubed. Use all the information to evaluate the effectiveness and safety of this treatment. So whenever you've got an evaluate question, there are some standard things to look for. So things like the sample size, the duration, is there a statistical test to see if we've got a significant difference? Did they test it on individual cells or the entire organism? Did they test it on the same organism that they're making the conclusion from? What do the actual data results show in terms of effectiveness as well? So those are the sorts of things that we need to look for. So if we have a look um one thing that I'd point out is we've got any time when we've got patients with a T helps let me just here help cell count of 24 months.

[00:20:55]So for this one that is greater than 200 whereas the placebo is less than 200. So that's one thing that I'd be picking out from the data. So um alpha cell count greater than 200 for test group less than 100 for placebo shows it is effective.

[00:21:39]Um then let's have a look at the next thing.

[00:21:45]Did see an increase. So I might also add that whereas this one saw a decrease. So test group had add an increase in T alpha cells.

[00:22:04]Then the next bit patients with THL less than. Okay. So for this one only one patient was so for test group only one patient less than one. Uh but the downside look at that five of them had side effects.

[00:22:29]So those are all positives.

[00:22:31]negatives.

[00:22:33]Five had side effects.

[00:22:38]Then a big one that a lot of people said was um that there was a small sample size. I was going to say small sample size.

[00:22:54]Um and those how many marks it five. So, I think I'd go for those five as my key marking points. So, next thing is you've got only 24 months, but 24 months that I think some people would argue that's quite long. Some people say it's quite short, so you couldn't necessarily have that one. So, let's just move on to I think that nearly takes us to the end. Very, very close end. Explain how vaccination against the path provides protection if the pathogen is encountered again in the future. So we've got a vaccination question. The first thing I'd be saying is that the vaccine introduces um vaccinees and cells. Go final expansion and make cells and memory B cells.

[00:24:13]Memory B cells remain in the blood.

[00:24:25]So if reinfected with the same antigen, you would make antibodies rapidly. So you need the idea that it's rapidly and in large.

[00:24:48]Okay, so last one. Some good answers coming in there. Some vaccines require booster doses to maintain protection.

[00:24:57]Guess why? Um, so different ideas you could go for here because it could be antigenic variability.

[00:25:09]you need to have boosters. Um, or you could have that of memory B cells increase or you could have antigenic variability.

[00:25:31]Okay. Right. That takes us to the end of those exam questions. So that is the final part for today. But you can, as I said, join me tomorrow at 12:30.

[00:25:48]We decided what we were doing. Oh, we're doing transllocation. So transllocation implants. And then if you need help with the practicals for paper one, I'll put the link into the chat or if you're watching on um Instagram, then you just need to type pick 26 on Instagram to get the link. Click the link there. But that was it for this evening, everyone. Thank you so much for joining my revision today. I know some of you were here this afternoon and this evening. So I hope it helped and best of luck with your revision and see you tomorrow. Um, tomorrow morning's pick a mix is at 10:00 a.m. on practicals. The half an hour live, as it says at the top here, that'll be at 12:30 p.m. Pick a mix one is not free because it's an hour long.

[00:26:30]You get the recording, you get the slides, and you get a workbook as well.

[00:26:34]The half an hour session at lunchtime is free because you don't get any resources with it. It's just half an hour bit like this one. Um, okay. So I will see you