HIV is one of the most significant viral infections affecting... Show more
SociologySign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
117
•
4 Dec 2025
•
Understanding HIV: AQA A-Level Biology Notes
Amala Seth
@amala_seth
Understanding HIV and Pathogen Defence
You'll encounter four main types of pathogenic organisms in your studies: bacteria, viruses, fungi, and plasmodium. When it comes to fighting infections that hide inside cells, your body relies on cytotoxic T-cells as the primary defence force.
Human immunodeficiency virus (HIV) causes acquired immune deficiency syndrome (AIDS) and has a unique structure that makes it particularly dangerous. The virus has a lipid envelope studded with GP120 proteins that latch onto CD4 receptors on immune cells. Inside this envelope sits a capsid containing two single RNA strands and crucial enzymes.
The two key enzymes are reverse transcriptase (which makes DNA from RNA) and integrase (which inserts viral DNA into your host cell's DNA). This sophisticated setup allows HIV to hijack your cells completely.
Quick Fact: Vaccines provide artificial active immunity, but HIV's constantly changing nature makes vaccine development incredibly challenging.
HIV Replication and Impact on Immunity
HIV replication follows a seven-step process that's absolutely devastating to your immune system. After the virus fuses with a host cell and enters, reverse transcription creates viral DNA that gets transported to the nucleus and integrated into your cell's own DNA.
The hijacked cell then produces new viral RNA and proteins, which assemble at the cell surface to form immature HIV particles. Finally, an enzyme called protease releases proteins that create mature, infectious HIV ready to attack more cells.
HIV specifically targets helper T-cells, either killing them or disrupting their normal function. With fewer helper T-cells in your blood, your immune system can't properly stimulate B-cells to produce antibodies, leaving you vulnerable to opportunistic infections and cancers.
Antibiotics are useless against HIV because viruses lack their own metabolic pathways and cell structures - there's simply nothing for antibiotics to disrupt. HIV is classified as a retrovirus because it carries RNA and those two crucial enzymes that allow it to reverse the normal flow of genetic information.
Remember: Understanding HIV's replication cycle helps explain why combination drug therapies target different stages of infection.
We thought you’d never ask...
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.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Most popular content: Hiv and Aids
Most popular content in Biology
Most popular content
English - inspector calls quotes and analysis
Quotes from every main character
English Literature10
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
Understanding HIV: AQA A-Level Biology Notes
Amala Seth
@amala_seth
HIV is one of the most significant viral infections affecting millions worldwide, causing AIDS by systematically destroying the immune system. Understanding how this retrovirus works is crucial for grasping modern immunology and public health challenges.
Understanding HIV and Pathogen Defence
You'll encounter four main types of pathogenic organisms in your studies: bacteria, viruses, fungi, and plasmodium. When it comes to fighting infections that hide inside cells, your body relies on cytotoxic T-cells as the primary defence force.
Human immunodeficiency virus (HIV) causes acquired immune deficiency syndrome (AIDS) and has a unique structure that makes it particularly dangerous. The virus has a lipid envelope studded with GP120 proteins that latch onto CD4 receptors on immune cells. Inside this envelope sits a capsid containing two single RNA strands and crucial enzymes.
The two key enzymes are reverse transcriptase (which makes DNA from RNA) and integrase (which inserts viral DNA into your host cell's DNA). This sophisticated setup allows HIV to hijack your cells completely.
Quick Fact: Vaccines provide artificial active immunity, but HIV's constantly changing nature makes vaccine development incredibly challenging.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
HIV Replication and Impact on Immunity
HIV replication follows a seven-step process that's absolutely devastating to your immune system. After the virus fuses with a host cell and enters, reverse transcription creates viral DNA that gets transported to the nucleus and integrated into your cell's own DNA.
The hijacked cell then produces new viral RNA and proteins, which assemble at the cell surface to form immature HIV particles. Finally, an enzyme called protease releases proteins that create mature, infectious HIV ready to attack more cells.
HIV specifically targets helper T-cells, either killing them or disrupting their normal function. With fewer helper T-cells in your blood, your immune system can't properly stimulate B-cells to produce antibodies, leaving you vulnerable to opportunistic infections and cancers.
Antibiotics are useless against HIV because viruses lack their own metabolic pathways and cell structures - there's simply nothing for antibiotics to disrupt. HIV is classified as a retrovirus because it carries RNA and those two crucial enzymes that allow it to reverse the normal flow of genetic information.
Remember: Understanding HIV's replication cycle helps explain why combination drug therapies target different stages of infection.
We thought you’d never ask...
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.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
2
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Mock Exam
Quiz
Flashcards
Essay
Similar content
HIV Transmission & Replication
Explore the key concepts of HIV, including its transmission methods, structure, and replication process. This summary covers the lifecycle of the HIV virus, its impact on helper T cells, and the progression to AIDS. Ideal for AQA A-Level Biology students focusing on pathogens and viral infections.
Biology12
HIV & Immunology Overview
Explore the key concepts of HIV replication and the immune response in this comprehensive summary. Understand the roles of T helper cells, B cells, and cytotoxic T cells in the adaptive immune response, along with the ELISA test procedure for antigen detection. Ideal for AQA A-Level Biology students preparing for Paper 1.
Biology12
Understanding Antibodies
Explore the structure and function of antibodies in the immune system, including their role in agglutination, memory cells, and monoclonal antibodies. This summary covers key concepts such as the enzyme-substrate complex and the ELISA test, making it essential for AQA A-level Biology students.
Biology12
Understanding ELISA Tests
Explore the ELISA (enzyme-linked immunosorbent assay) testing method, focusing on its application in detecting prostate cancer and HIV antibodies. This summary covers the principles of direct and indirect testing, the role of antibodies, and the significance of color change in results. Ideal for AQA A-Level Biology students studying immunology and biological defenses.
Biology12
Understanding Specific Immunity
Explore the intricacies of the specific immune system, covering key concepts such as phagocytes, antibodies, lymphocytes, humoral immunity, and the primary and secondary immune responses. This comprehensive summary is essential for mastering OCR A A-level Biology and understanding autoimmune diseases.
Biology12
Understanding Vaccination Mechanisms
Explore the essential concepts of vaccination, including types of immunity (active, passive, natural, artificial), how vaccines stimulate immune responses, and the importance of herd immunity. This summary provides insights into the ethical considerations surrounding vaccines and their effectiveness against antigenic variability. Ideal for AQA A-level Biology students.
Biology12
Most popular content: Hiv and Aids
Most popular content in Biology
Most popular content
English - inspector calls quotes and analysis
Quotes from every main character
English Literature10
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