﻿Just take a moment to note down the date and the title so that you can keep all of your notes organised. Hi, I'm Ms. Todd and welcome to your second review lesson of this topic. Can you make sure that you've got a nice quiet place to work and that you've turned off all the notifications on your devices if you know how to. Just so that you won't be distracted during the lesson for this lesson. For this lesson you're going to need a pen and some paper. So if you've got colour pens that would be great but don't worry if you don't. Also you'll need one sheet of A4 to write on, but also also three sheets of A4 cut up into squares if you can, as we're going to be making revision cards today. If you haven't got those things, can you pause now and just get those ready before you start the lesson. So in today's lesson, we're going to review immunity, vaccines, antibiotics, and testing drugs. So we'll start off by looking at immunity. So what happens if pathogens actually do get into our body? Well most of us will have been ill with an infectious disease at some point. And that means that they've got past our defences and they've made us ill by damaging our cells and releasing toxins. But we've managed to get better. So somehow our body has been able to destroy these pathogens. Our white blood cells are the ones that destroy the pathogens that do manage to get into the body. And they work to neutralise the effects of toxins. So the pathogens make us ill by damaging our cells and tissues when they reproduce or when they release toxins. Our white blood cells destroy pathogens that do get into our body and they neutralise the effects of toxins. So white blood cells can destroy these pathogens in three ways. By ingesting and destroying the pathogens directly. So this is called phagocytosis. By releasing antitoxins and releasing antibodies. But just to have a few quick fire questions just to see what you can remember. What do antibodies bind to? Excellent. The antigens of the pathogen. What do the white blood cells release in response to toxins? Just shout the answer for me. Wonderful. They release antitoxins. So if we start by looking at the primary and secondary immune response. So the primary immune response is when the pathogen first enters our body for the very first time. Now the primary response is a bit slow. It takes a few days for these to be made so that they can destroy the pathogen. And this is called lag time. However, after that primary exposure, these white blood cells remember how to make these antibodies. So they form memory cells. So that means if a pathogen gets in for a second time, remember it's got to be the same pathogen. When it gets in for a second time, these white blood cells remember how to make those antibodies. So they can produce these antibodies much faster and much more of them. So the secondary response is faster because they already remember how to make these antibodies. And that means they can make much more of them in that timeframe so that we can destroy the pathogen before these symptoms are even felt. If the pathogen has been destroyed before you feel any symptoms, we would say you are immune to that pathogen. So white blood cells form memory cells. This means that they remember how to make the same antibodies if that same pathogen ever gets into the body again. So for example if the virus that causes measles was to get into your body, the pathogen would be destroyed and the white blood cells would remember how to make the antibodies to fight off the measles virus. But this wouldn't do anything for if you were then infected with salmonella. So it's got to be the same pathogen. And this allows your immune system to respond much more quickly because they can get these antibodies made really fast and they can make a lot more of them. Which means that the pathogen can be destroyed before you feel symptoms. So you must say that the white blood cells remember how to produce the antibodies, not that they remember how to fight it off. Cause they don't remember how to fight the pathogen off at all. They just remember how to make those specific antibodies for that pathogen. So immunity. We say that someone is immune if their immune system is able to respond fast enough that a pathogen is destroyed before any symptoms can be felt. This is because the white blood cells have been able to make and release antibodies so fast that the pathogen has been destroyed before any symptoms have been felt. Immunity can be passed on. So babies that are breastfed, receive antibodies in the breast milk. And that allows them protection during the early days of life. Just pause here and have a read of those key points. What I would like you to do on your sheet of paper, fill in the gaps in these sentences. Brilliant. The secondary response is faster because the white blood cells form memory cells. This means they remember to produce the antibody for that specific pathogen. So more antibodies can be made quicker. So I'm going to take you through how to make some revision cards. So you should have already cut up three pieces of A4 into squares. If you haven't done that, can you just pause and do that now. Excellent. So with a revision card, on one side you have the question and on the other side you have the answer. So you memorise the answers to these questions and you can test yourself really quickly on the basic knowledge of the topic. So here I've chosen the question, what do the white blood cells release in response to toxins? So that is my question on one side of this card. I would then write the answer, antitoxins on the other. What I would like you to do is pause here and make this your first revision card. So you put the question on one side and the answer on the other. What I would like you to do now is, pause here and turn these three questions into revision cards for me. So you put one question on each card, with the answer on the back. Excellent, so this is what your question on one side and the answer on the other should look like. If you need to add in any detail, please do so. So now we're going to have a recap of vaccines. So the pathogen that causes the disease is weakened so that it won't cause illness when it's injected into your body. So for example, a vaccine against tetanus would contain a small number of weakened bacterial cells that cause tetanus. The vaccine is injected into the body and this stimulates the white blood cells to produce antibodies for that pathogen. They then formed memory cells which remember how to produce this specific antibody. All this is done without making the person ill because the pathogen has been weakened. If the vaccinated person is later infected by that same pathogen, their immune system will respond much more quickly because these memory cells remember how to produce these antibodies. That means that the pathogen can be destroyed before their symptoms are felt. And this is known as immunity. Again, please pause here and just have a read of those main points about vaccines. So the advantages of vaccines are that it's a safe and cost effective way of preventing an outbreak of disease. Smallpox has been completely eradicated by using vaccination and polio could be next. So Edward Jenner discovered the first vaccine for smallpox as he realised that milkmaids that had cowpox were not being infected with smallpox. If enough people are vaccinated, even people that have not been vaccinated are protected because the pathogen can no longer spread. This is what we call herd immunity. So what does a vaccine contain? Brilliant. A dead or weakened form of the pathogen. What is the term for when unvaccinated people are still protected because the pathogen can not spread? Good, it's herd immunity. Which disease has been completely eradicated because of vaccines? Excellent. Smallpox. Who discovered the first vaccine for smallpox? It was Edward Jenner. So general exam, we need to make sure that we're getting our ideas down in a scientific way. So we need to make sure that we're using correct scientific language. So this student wrote in an exam, we can't use antibiotics to treat viruses because viruses are immune. This statement will get no marks in exam. Why do you think that? Well, they've said that viruses are immune. And we know that immunity is when a pathogen is destroyed before any symptoms are felt. So this statement here is not scientifically accurate and therefore they would be getting no marks for this statement. Instead they should have wrote, we can't use antibiotics to treat viral infections because viruses are inside our cells. So just by being specific about why the antibiotic cannot treat the virus, they've gained a mark. What I would like you to do is rewrite these three statements and make them more scientifically accurate. Just check your answers against the answers on the screen. If you need to make any changes, please do so. So we're going to look now at antibiotics. So there are two kinds of medicines that we can use to treat infectious disease. So over the counter medications help you feel better, but they do not kill the pathogen. So they ease the symptoms of the disease, but they do not get rid of the disease. They just make you feel better so that you can continue with life while your body fights off this pathogen. Antibiotics however, kill pathogenic bacteria inside the body. Here's a quick question, why do antibiotics not treat viruses? Shout that out for me. Excellent. Antibiotics don't treat viruses because viruses are inside our cells and they can not reach them. Antibiotics work by killing pathogenic bacteria inside the body. The first antibiotic was penicillin. And this was discovered in the last century by Alexander Fleming from the mould penicillium. Their introduction was thought to signal the end of most serious diseases. And to a certain extent it has. However, scientists are always looking for new antibiotics as pathogens can change quickly and become resistant to antibiotics. Just shout out for me. Why would we use over the counter medicine? Brilliant, so we use these painkillers to treat the symptoms of disease. So they don't actually kill the pathogen, they just ease the symptoms while your body fights off the pathogen. What do antibiotics do? Good. They kill pathogenic bacteria in the body. Who discovered penicillin? Well done, Alexander Fleming. So how do the doctors or people prescribing know which antibiotic is best to use? So what you can see here is an agar plate that has had bacteria grown on it. So this might have been a swab from an infected person that has been grown on the agar, and different antibiotics have been placed on top. So ABC and D are all different antibiotics. Now as you can see around these antibiotics, there is a zone of inhibition where the bacteria has not grown because these antibiotics have killed the pathogenic bacteria. So the most effective antibiotic is the one with the biggest clear zone. So for this particular infection, antibiotic D would be prescribed. Because it has the biggest zone of inhibition. This isn't always done as many antibiotics are broad spectrum. Which means that they can treat a variety of different bacterial infections. This would only be done if you had a persistent infection that antibiotics had failed to clear up so that they could find the one that was right for you. What was the area around the disc called? Excellent, it was zone of inhibition or it might be called the clear zone. How do we find the radius of the circle? We halve the diameter. So you might remember in the antibiotics lesson, we measured the diameter of a clear zone and we halved that diameter to find the radius, so that we could use the Pi R squared equation to find the area of those clear zones. How do we find the area of the circle? I've just given you a hint in the explanation before. Good. Area equals Pi R squared. So what I'd like you to do now is again, turn each of these questions into revision card. So you need to write your question on one side and your answer on the back. Brilliant, this is what your questions and answers should look like. So you've got your question on one side and your answer on the back. Just check your answers against the answers on screen. So we're now just going to recap testing drugs. A new drug can be extracted from plants or from microorganisms. So on one side we've got the drugs and on the other side we've got the plants or microorganisms that these drugs could have been extracted from. What I would like you to do is match these up. So match the plant and the microorganism to the correct drug. Excellent. So aspirin is derived from willow, digitalis comes from foxgloves and the penicillin comes from the penicillium mould, which was discovered by Alexander Fleming. So these are the stages of drug development. What I'd like you to do is, pause here and just make yourself familiar with these stages. So now we're just going to go over what a placebo is. So placebo is a fake or dummy treatment that looks exactly the same as the drug that is being tested. During clinical trials, one group of participants are given the actual drug and the other are given a dummy drug that has no effect. That's the placebo. The placebo looks identical to the real drug. So there are no clues as to who is taking the real drug and who is taking the placebo. During all phases of clinical trials, one group is given the real drug and one group has given the placebo. This is called a double blind trial. So that's when neither the scientists or the participants know who is taking that real drug. And this prevents bias. What is a placebo? Shout that out for me. Brilliant. A dummy treatment. What is efficacy? Excellent, so efficacy is how effective the drug is. So how good is it doing what the scientists say it should do? Why is the drug tested on cell cultures? Brilliant. It tests the toxicity. So that's just making sure that it's not toxic before we give it to people. What I would like you to do is turn each of these questions into a revision card. Good, so you've got your question on one side, your answer it on the other. So that brings us to the end of our second review lesson. I just want to say a very big thank you for all the hard work that you've put into this lesson today. It's been a quiet a hands-on lesson. What I'd like you to do is make sure that you keep testing yourself with these revision cards that you have made. Can you also please go and complete the exit quiz for me? I hope you have a wonderful rest of the day.

In this lesson we will revise immunity, vaccines, antibiotics and testing drugs. We will make sure we can use accurate scientific language and construct our own revision cards.

Combined Science

Y10 Combined Science (Higher)

Key Stage 4

Year 10

Miss

Review (Part 2)

Infection and response (HT)

UNIT

Infectious disease

Viral and bacterial disease

Fungal and protist disease

Immunity

Vaccines

Antibiotics

Maths skills

Testing drugs (Part 1)

Testing drugs (Part 2)

Review (Part 1)

Exam Skills

Kelly Chibale: Drug production

Y10 Combined Science (Foundation)

Infection and response (FT)

Biology

Y10 Biology

Infection and response

Monoclonal antibodies

Plant diseases and deficiencies (Part 1)

Plant diseases and deficiencies (Part 2)

Review (BIO ONLY)

Lesson overview: Review (Part 2)

Video

Presentation

Worksheet

Exit Quiz

Transcript

13 lessons in Infection and response (HT):

13 lessons in Infection and response (FT):

17 lessons in Infection and response: