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Get an A* in A Level Biology: Immune System Notes for AQA Year 12 & 13
The Immune System: Cellular and Humoral Responses
The immune system is a sophisticated defense mechanism that protects the body against pathogens and foreign substances. This page delves into the cellular and humoral responses, which are crucial components of the immune system's functionality.
The immune response is triggered by antigens, which are molecules found on the surface of cells that the immune system uses to identify pathogens, abnormal body cells, toxins, and cells from other individuals of the same species. The response is divided into two main categories: cellular and humoral.
Definition: Antigens are molecules that can generate an immune response when detected by the body. They are usually found on the surface of cells and are used by the immune system to identify foreign or abnormal entities.
The cellular response involves T-cells and other immune cells they interact with, such as phagocytes. The humoral response, on the other hand, focuses on B-cells and the production of monoclonal antibodies through clonal selection.
Vocabulary: Phagocytes are a type of white blood cell that engulfs and destroys foreign particles, bacteria, and dead or dying cells.
The immune response process begins with phagocytes engulfing pathogens. These cells recognize foreign antigens on pathogens, engulf them, and present the pathogen's antigens on their surface to activate other immune system cells.
Example: When a phagocyte encounters a bacterium, it engulfs it, breaks it down, and displays fragments of the bacterium's proteins on its surface.
T-cells, another type of white blood cell, are then activated by the antigens presented by phagocytes. Different types of T-cells respond in various ways. For instance, helper T-cells release chemical signals that stimulate phagocytes, while cytotoxic T-cells kill abnormal and foreign cells.
B-cells, also white blood cells, are covered with antibodies. When an antibody on a B-cell's surface meets a complementary shaped antigen, it binds to it. This process, along with substances released from T-cells, activates the B-cell in a process called clonal selection.
Highlight: The activation of B-cells through clonal selection is a crucial step in the production of specific antibodies to combat pathogens.
Activated B-cells divide into plasma cells, which secrete large quantities of antibodies specific to the antigen. These monoclonal antibodies bind to antigens on the pathogen's surface, forming antigen-antibody complexes. This process leads to the destruction of pathogens carrying the specific antigen in the body.
The immune system's response can be categorized into primary and secondary responses. The primary immune response occurs when an antigen enters the body for the first time. It is relatively slow because there aren't many B-cells that can produce the needed antibody. During this time, the infected person may show symptoms of the disease.
Vocabulary: Memory cells are long-lasting cells produced by both T-cells and B-cells after exposure to an antigen. They enable a faster and more effective immune response upon subsequent encounters with the same antigen.
After the primary response, both T-cells and B-cells produce memory cells. These cells remain in the body for an extended period, allowing for a quicker response to subsequent infections by the same pathogen.
The secondary immune response occurs when the same pathogen enters the body again. This response is faster and stronger than the primary response. Memory B-cells are quickly activated and divide into plasma cells that produce the right antibody to the antigen. Similarly, memory T-cells are activated and divide into the correct type of T-cells to kill cells carrying the antigen.
Highlight: The secondary immune response is often so rapid and effective that it can eliminate the pathogen before the person begins showing symptoms of the disease.
Understanding these intricate processes of the immune system is crucial for students aiming to excel in A-level Biology, particularly when studying topics related to cell recognition and the immune system. This knowledge forms the foundation for comprehending more complex immunological concepts and is essential for answering exam questions on immunity in A-level Biology.
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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.
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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.
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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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm sure you too will see developments.
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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 ๐๐๐ฒ๐ค๐โจ๐๐ฎ
Elisha
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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
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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 itโs 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
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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
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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
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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm 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 ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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
Get an A* in A Level Biology: Immune System Notes for AQA Year 12 & 13
The immune system is a complex network of cells and processes that protect the body from pathogens and foreign substances. This summary explores the cellular and humoral responses, key components of immunity, and the primary and secondary immune responses.... Show more
The Immune System: Cellular and Humoral Responses
The immune system is a sophisticated defense mechanism that protects the body against pathogens and foreign substances. This page delves into the cellular and humoral responses, which are crucial components of the immune system's functionality.
The immune response is triggered by antigens, which are molecules found on the surface of cells that the immune system uses to identify pathogens, abnormal body cells, toxins, and cells from other individuals of the same species. The response is divided into two main categories: cellular and humoral.
Definition: Antigens are molecules that can generate an immune response when detected by the body. They are usually found on the surface of cells and are used by the immune system to identify foreign or abnormal entities.
The cellular response involves T-cells and other immune cells they interact with, such as phagocytes. The humoral response, on the other hand, focuses on B-cells and the production of monoclonal antibodies through clonal selection.
Vocabulary: Phagocytes are a type of white blood cell that engulfs and destroys foreign particles, bacteria, and dead or dying cells.
The immune response process begins with phagocytes engulfing pathogens. These cells recognize foreign antigens on pathogens, engulf them, and present the pathogen's antigens on their surface to activate other immune system cells.
Example: When a phagocyte encounters a bacterium, it engulfs it, breaks it down, and displays fragments of the bacterium's proteins on its surface.
T-cells, another type of white blood cell, are then activated by the antigens presented by phagocytes. Different types of T-cells respond in various ways. For instance, helper T-cells release chemical signals that stimulate phagocytes, while cytotoxic T-cells kill abnormal and foreign cells.
B-cells, also white blood cells, are covered with antibodies. When an antibody on a B-cell's surface meets a complementary shaped antigen, it binds to it. This process, along with substances released from T-cells, activates the B-cell in a process called clonal selection.
Highlight: The activation of B-cells through clonal selection is a crucial step in the production of specific antibodies to combat pathogens.
Activated B-cells divide into plasma cells, which secrete large quantities of antibodies specific to the antigen. These monoclonal antibodies bind to antigens on the pathogen's surface, forming antigen-antibody complexes. This process leads to the destruction of pathogens carrying the specific antigen in the body.
The immune system's response can be categorized into primary and secondary responses. The primary immune response occurs when an antigen enters the body for the first time. It is relatively slow because there aren't many B-cells that can produce the needed antibody. During this time, the infected person may show symptoms of the disease.
Vocabulary: Memory cells are long-lasting cells produced by both T-cells and B-cells after exposure to an antigen. They enable a faster and more effective immune response upon subsequent encounters with the same antigen.
After the primary response, both T-cells and B-cells produce memory cells. These cells remain in the body for an extended period, allowing for a quicker response to subsequent infections by the same pathogen.
The secondary immune response occurs when the same pathogen enters the body again. This response is faster and stronger than the primary response. Memory B-cells are quickly activated and divide into plasma cells that produce the right antibody to the antigen. Similarly, memory T-cells are activated and divide into the correct type of T-cells to kill cells carrying the antigen.
Highlight: The secondary immune response is often so rapid and effective that it can eliminate the pathogen before the person begins showing symptoms of the disease.
Understanding these intricate processes of the immune system is crucial for students aiming to excel in A-level Biology, particularly when studying topics related to cell recognition and the immune system. This knowledge forms the foundation for comprehending more complex immunological concepts and is essential for answering exam questions on immunity in A-level Biology.
Can't find what you're looking for? Explore other subjects.
Students love us โ 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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm 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 ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm 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 ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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