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14 Dec 2025
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GCSE Edexcel Biology Topic 5: Health and Disease
EH
@e_mountain123
Understanding Health and Disease
Your health isn't just about not being sick—it's about complete mental and physical well-being. Diseases fall into two main categories: communicable diseases (spread by pathogens like bacteria, fungi, and viruses) and non-communicable diseases (like obesity and cardiovascular disease).
Cardiovascular disease is a serious health concern that develops when fatty deposits damage blood vessels. These deposits restrict blood flow, increasing pressure and potentially causing strokes (when blood can't reach the brain) or heart attacks (when blood can't reach the heart muscle). Risk factors include a diet high in saturated fat, lack of exercise, and smoking—all of which can increase your chances of developing this condition.
Treatment options range from lifestyle changes to medical interventions. Doctors might prescribe statins or anti-coagulants to manage cholesterol and prevent clots. More serious cases might need stents (small mesh tubes that keep blood vessels open), bypass surgery (creating a new path for blood flow), or in extreme cases, heart transplants.
Did you know? Doctors can test antibiotic effectiveness by measuring the "zone of inhibition"—the area where bacteria can't grow around an antibiotic disk placed on a culture plate.
Plants have their own defence systems against diseases. Physical barriers include waxy cuticles and bark that block pathogens, while chemical defences include toxins and antibacterial compounds. When scientists study plant diseases, they use aseptic techniques to prevent contamination—like sterilising equipment and limiting exposure to air.
Viruses operate differently from other pathogens. These non-living particles need host cells to reproduce through either the lytic cycle (where they quickly multiply and burst the cell) or the lysogenic cycle (where viral DNA incorporates into the host's DNA and activates later). This explains why viral infections can sometimes appear dormant before suddenly becoming active.
Fighting Disease
Your body has impressive defence systems against pathogens. Physical barriers include your skin (an impermeable shield), mucus (trapping invaders), and hairs in your nose and ears. Chemical defences like saliva (containing the enzyme lysozyme) and stomach acid work to destroy pathogens before they can cause harm.
Vaccines are a brilliant way to prepare your immune system for potential threats. They introduce weakened pathogens so your body can produce antibodies without getting sick. Memory lymphocytes then remain in your bloodstream, ready to quickly produce antibodies if the real pathogen ever appears. This gives you immunity without suffering through the actual disease.
Monoclonal antibodies are laboratory-created immune proteins that can target specific antigens. Scientists create them by fusing lymphocytes with tumor cells to produce "hybridomas" that can continuously produce identical antibodies. These have practical applications like pregnancy tests, where the antibodies detect specific hormones in urine.
Remember this: When pathogens enter your bloodstream, specialized white blood cells called phagocytes engulf them and present their antigens to T cells, which then coordinate the immune response.
The immune system works through recognition and response. When pathogens enter your body, phagocytes engulf them while lymphocytes produce specific antibodies that bind to the pathogen's antigens. This disables the pathogen and flags it for destruction. Memory lymphocytes remain afterward, providing quicker protection if the same pathogen returns—this is called the secondary response.
Drug development follows a careful process to ensure safety and effectiveness. It begins with lab testing on cells, followed by pre-clinical testing on animals, and finally clinical testing on humans. These clinical trials often use double-blind methods (where neither doctors nor patients know who receives the actual drug) to prevent bias in evaluating results.
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Thomas R
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Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
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This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
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In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
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very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
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I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
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THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
GCSE Edexcel Biology Topic 5: Health and Disease
EH
@e_mountain123
Health and Disease explores the spectrum of human well-being beyond just the absence of illness. This topic covers how diseases spread, affect our bodies, and how we fight them using both natural defences and medical interventions.
Understanding Health and Disease
Your health isn't just about not being sick—it's about complete mental and physical well-being. Diseases fall into two main categories: communicable diseases (spread by pathogens like bacteria, fungi, and viruses) and non-communicable diseases (like obesity and cardiovascular disease).
Cardiovascular disease is a serious health concern that develops when fatty deposits damage blood vessels. These deposits restrict blood flow, increasing pressure and potentially causing strokes (when blood can't reach the brain) or heart attacks (when blood can't reach the heart muscle). Risk factors include a diet high in saturated fat, lack of exercise, and smoking—all of which can increase your chances of developing this condition.
Treatment options range from lifestyle changes to medical interventions. Doctors might prescribe statins or anti-coagulants to manage cholesterol and prevent clots. More serious cases might need stents (small mesh tubes that keep blood vessels open), bypass surgery (creating a new path for blood flow), or in extreme cases, heart transplants.
Did you know? Doctors can test antibiotic effectiveness by measuring the "zone of inhibition"—the area where bacteria can't grow around an antibiotic disk placed on a culture plate.
Plants have their own defence systems against diseases. Physical barriers include waxy cuticles and bark that block pathogens, while chemical defences include toxins and antibacterial compounds. When scientists study plant diseases, they use aseptic techniques to prevent contamination—like sterilising equipment and limiting exposure to air.
Viruses operate differently from other pathogens. These non-living particles need host cells to reproduce through either the lytic cycle (where they quickly multiply and burst the cell) or the lysogenic cycle (where viral DNA incorporates into the host's DNA and activates later). This explains why viral infections can sometimes appear dormant before suddenly becoming active.
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Fighting Disease
Your body has impressive defence systems against pathogens. Physical barriers include your skin (an impermeable shield), mucus (trapping invaders), and hairs in your nose and ears. Chemical defences like saliva (containing the enzyme lysozyme) and stomach acid work to destroy pathogens before they can cause harm.
Vaccines are a brilliant way to prepare your immune system for potential threats. They introduce weakened pathogens so your body can produce antibodies without getting sick. Memory lymphocytes then remain in your bloodstream, ready to quickly produce antibodies if the real pathogen ever appears. This gives you immunity without suffering through the actual disease.
Monoclonal antibodies are laboratory-created immune proteins that can target specific antigens. Scientists create them by fusing lymphocytes with tumor cells to produce "hybridomas" that can continuously produce identical antibodies. These have practical applications like pregnancy tests, where the antibodies detect specific hormones in urine.
Remember this: When pathogens enter your bloodstream, specialized white blood cells called phagocytes engulf them and present their antigens to T cells, which then coordinate the immune response.
The immune system works through recognition and response. When pathogens enter your body, phagocytes engulf them while lymphocytes produce specific antibodies that bind to the pathogen's antigens. This disables the pathogen and flags it for destruction. Memory lymphocytes remain afterward, providing quicker protection if the same pathogen returns—this is called the secondary response.
Drug development follows a careful process to ensure safety and effectiveness. It begins with lab testing on cells, followed by pre-clinical testing on animals, and finally clinical testing on humans. These clinical trials often use double-blind methods (where neither doctors nor patients know who receives the actual drug) to prevent bias in evaluating results.
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What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
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Most popular content: Cardiovascular Diseases
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Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user