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AQA A-Level Biology HIV Exam Revisions PDF Free

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AQA A-Level Biology HIV Revision Notes

1,222

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5 Jul 2025

โ€ข

1 page

AQA A-Level Biology HIV Exam Revisions PDF Free

HIV: Structure, Transmission, and Replication in the Human Body

HIV,... Show more

HIV
Transmission
โ†ณ HIV is a retrovinus.
L it is unable to survive outside the human body
can be transmitted in the following ways:
is sharin

HIV: Structure, Transmission, and Replication

HIV Structure and Transmission

HIV, or Human Immunodeficiency Virus, is a retrovirus that cannot survive outside the human body. Its structure is complex, consisting of several key components that enable its infectious capabilities.

Highlight: HIV's structure includes two RNA strands, proteins includingreversetranscriptaseincluding reverse transcriptase, a protein capsid, and a viral envelope made of a lipid bilayer with glycoproteins.

The virus can be transmitted through various means, all involving the exchange of bodily fluids:

  • Sexual intercourse
  • Sharing of needles by intravenous drug users
  • Mother-to-child transmission across the placenta or through breast milk
  • Blood transfusions thoughthisisnowrareduetoscreeningthough this is now rare due to screening

Vocabulary: Retrovirus - A type of virus that uses RNA as its genetic material and requires reverse transcription to replicate.

HIV Replication Process

The replication of HIV within the human body is a multi-step process that targets helper T cells, a crucial component of the immune system.

  1. Entry: HIV enters the bloodstream and infects helper T cells.
  2. Reverse Transcription: Viral RNA is converted to DNA using reverse transcriptase.
  3. Integration: The viral DNA is inserted into the host cell's chromosomes.
  4. Latency: Infected cells remain normal as viral DNA is inactive.
  5. Activation: After a period, viral DNA becomes active and takes control of the helper T cell.
  6. Production: New HIV particles are produced, causing the host cell to die and release thousands of new viruses.

Example: During the latency period, an individual is HIV-positive and will have antibodies against the virus, but may not show symptoms of AIDS.

The gradual destruction of helper T cells impairs the immune system's ability to fight off infections:

  • B cells are no longer activated, leading to reduced antibody production.
  • The body's ability to combat infections decreases, eventually leading to AIDS.

Definition: AIDS AcquiredImmunodeficiencySyndromeAcquired Immunodeficiency Syndrome - The final stage of HIV infection, characterized by a severely weakened immune system.

Quote: "HIV avoids being recognised and destroyed by lymphocytes by repeatedly changing its protein coat."

This detailed understanding of HIV's structure, transmission, and replication is crucial for A Level Biology HIV exam questions and provides a foundation for comprehending the virus's impact on the human immune system.



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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 itโ€™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 didnโ€™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 Iโ€™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 ๐Ÿ˜๐Ÿ˜๐Ÿ˜ฒ๐Ÿค‘๐Ÿ’—โœจ๐ŸŽ€๐Ÿ˜ฎ

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 itโ€™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 didnโ€™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 Iโ€™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 ๐Ÿ˜๐Ÿ˜๐Ÿ˜ฒ๐Ÿค‘๐Ÿ’—โœจ๐ŸŽ€๐Ÿ˜ฎ

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

ย 

Biology

โ€ข

1,222

โ€ข

5 Jul 2025

โ€ข

1 page

AQA A-Level Biology HIV Exam Revisions PDF Free

HIV: Structure, Transmission, and Replication in the Human Body

HIV, a retrovirus that attacks the immune system, is a complex pathogen with significant implications for human health. This summary explores the structure of HIV, its transmission methods, and its replication... Show more

HIV
Transmission
โ†ณ HIV is a retrovinus.
L it is unable to survive outside the human body
can be transmitted in the following ways:
is sharin

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HIV: Structure, Transmission, and Replication

HIV Structure and Transmission

HIV, or Human Immunodeficiency Virus, is a retrovirus that cannot survive outside the human body. Its structure is complex, consisting of several key components that enable its infectious capabilities.

Highlight: HIV's structure includes two RNA strands, proteins includingreversetranscriptaseincluding reverse transcriptase, a protein capsid, and a viral envelope made of a lipid bilayer with glycoproteins.

The virus can be transmitted through various means, all involving the exchange of bodily fluids:

  • Sexual intercourse
  • Sharing of needles by intravenous drug users
  • Mother-to-child transmission across the placenta or through breast milk
  • Blood transfusions thoughthisisnowrareduetoscreeningthough this is now rare due to screening

Vocabulary: Retrovirus - A type of virus that uses RNA as its genetic material and requires reverse transcription to replicate.

HIV Replication Process

The replication of HIV within the human body is a multi-step process that targets helper T cells, a crucial component of the immune system.

  1. Entry: HIV enters the bloodstream and infects helper T cells.
  2. Reverse Transcription: Viral RNA is converted to DNA using reverse transcriptase.
  3. Integration: The viral DNA is inserted into the host cell's chromosomes.
  4. Latency: Infected cells remain normal as viral DNA is inactive.
  5. Activation: After a period, viral DNA becomes active and takes control of the helper T cell.
  6. Production: New HIV particles are produced, causing the host cell to die and release thousands of new viruses.

Example: During the latency period, an individual is HIV-positive and will have antibodies against the virus, but may not show symptoms of AIDS.

The gradual destruction of helper T cells impairs the immune system's ability to fight off infections:

  • B cells are no longer activated, leading to reduced antibody production.
  • The body's ability to combat infections decreases, eventually leading to AIDS.

Definition: AIDS AcquiredImmunodeficiencySyndromeAcquired Immunodeficiency Syndrome - The final stage of HIV infection, characterized by a severely weakened immune system.

Quote: "HIV avoids being recognised and destroyed by lymphocytes by repeatedly changing its protein coat."

This detailed understanding of HIV's structure, transmission, and replication is crucial for A Level Biology HIV exam questions and provides a foundation for comprehending the virus's impact on the human immune system.

We thought youโ€™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 โ€“ all at your fingertips.

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 itโ€™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 didnโ€™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 Iโ€™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 ๐Ÿ˜๐Ÿ˜๐Ÿ˜ฒ๐Ÿค‘๐Ÿ’—โœจ๐ŸŽ€๐Ÿ˜ฎ

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 itโ€™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 didnโ€™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 Iโ€™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 ๐Ÿ˜๐Ÿ˜๐Ÿ˜ฒ๐Ÿค‘๐Ÿ’—โœจ๐ŸŽ€๐Ÿ˜ฎ

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