HIV A level Biology Watch

username3675004
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Is this right?:

HIV enters through bodily fluids

Viral glycoproteins attach themselves to CD4 receptors on the membrane of T-helper cells

HIV enters the cell by endocytosis

It releases reverse transcriptase and RNA

The reverse transcriptase copies single stranded RNA into double stranded DNA

The host cell thinks this is its own DNA and makes copies of the HIV DNA in its nucleus

Pls correct anything which is wrong. Thank you
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Jpw1097
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(Original post by 75321824)
Is this right?:

HIV enters through bodily fluids

Viral glycoproteins attach themselves to CD4 receptors on the membrane of T-helper cells

HIV enters the cell by endocytosis

It releases reverse transcriptase and RNA

The reverse transcriptase copies single stranded RNA into double stranded DNA

The host cell thinks this is its own DNA and makes copies of the HIV DNA in its nucleus

Pls correct anything which is wrong. Thank you
It looks correct. It's a very brief outline but looks correct to me.

Gp120 (a glycoprotein) on the surface of HIV binds to CD4 on the surface of CD4+ T cells and macrophages. Secondly, gp120 binds to CCR5 or CXCR4, a coreceptor also expressed by macrophages and CD4+ T cells - this causes the lipid envelope to fuse with the plasma membrane, allowing HIV to enter the host cell via endocytosis. Once inside the host cell, HIV releases HIV-1 protease, DNA integrase, reverse transcriptase as well as the viral RNA into the cytoplasm. Reverse transcriptase creates double-stranded DNA from the RNA (this is very error prone, which is why HIV has a very high mutation rate). The dsDNA then enters the nucleus and is integrated into the host genome using DNA integrase. The host cell now transcribes the provirus as if it were self, and produces viral RNA. Some of this acts as mRNA, and is translated into viral proteins (such as reverse transcriptase, integrase, gp120, HIV-1 protease, as well as the capsid) while some will become the viral RNA within new virions. The viral RNA and proteins then move to the plasma membrane where they bud from the cell, taking some of the plasma membrane with it forming the lipid envelope containing gp120. However, the budded virion is still immature and non-infectious. HIV-1 protease must first break down a large polyprotein into the capsid and matrix proteins. After this, the budded virion is mature and can infect other cells.
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username3675004
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(Original post by Jpw1097)
It looks correct. It's a very brief outline but looks correct to me.

Gp120 (a glycoprotein) on the surface of HIV binds to CD4 on the surface of CD4+ T cells and macrophages. Secondly, gp120 binds to CCR5 or CXCR4, a coreceptor also expressed by macrophages and CD4+ T cells - this causes the lipid envelope to fuse with the plasma membrane, allowing HIV to enter the host cell via endocytosis. Once inside the host cell, HIV releases HIV-1 protease, DNA integrase, reverse transcriptase as well as the viral RNA into the cytoplasm. Reverse transcriptase creates double-stranded DNA from the RNA (this is very error prone, which is why HIV has a very high mutation rate). The dsDNA then enters the nucleus and is integrated into the host genome using DNA integrase. The host cell now transcribes the provirus as if it were self, and produces viral RNA. Some of this acts as mRNA, and is translated into viral proteins (such as reverse transcriptase, integrase, gp120, HIV-1 protease, as well as the capsid) while some will become the viral RNA within new virions. The viral RNA and proteins then move to the plasma membrane where they bud from the cell, taking some of the plasma membrane with it forming the lipid envelope containing gp120. However, the budded virion is still immature and non-infectious. HIV-1 protease must first break down a large polyprotein into the capsid and matrix proteins. After this, the budded virion is mature and can infect other cells.
Thanks you!! I’m actually still doing GCSE rn but got a bit bored so taught myself a bit of A level stuff haha. Do I seriously need to know all that for A level?😵😵
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Jpw1097
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(Original post by 75324108)
Thanks you!! I’m actually still doing GCSE rn but got a bit bored so taught myself a bit of A level stuff haha. Do I seriously need to know all that for A level?😵😵
Definitely not. I just thought it would be an interesting read, I should have probably mentioned that. That's exactly what I used to do when I was doing my GCSEs, I would always read up on things to a much higher level than GCSE, and same at A level.
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username3675004
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(Original post by Jpw1097)
Definitely not. I just thought it would be an interesting read, I should have probably mentioned that. That's exactly what I used to do when I was doing my GCSEs, I would always read up on things to a much higher level than GCSE, and same at A level.
Phew! Thanks for the whole para tho! I just feel that if I do get some question on HIV and I answer it like this that I won’t get full marks bc it is too high level and not actually in the mark scheme haha....I think biology is really interesting when you read about it, although I can barely pronounce half the words I’m reading for the A level stuff lol😂
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Jaustin827
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(Original post by 75324350)
Phew! Thanks for the whole para tho! I just feel that if I do get some question on HIV and I answer it like this that I won’t get full marks bc it is too high level and not actually in the mark scheme haha....I think biology is really interesting when you read about it, although I can barely pronounce half the words I’m reading for the A level stuff lol😂
Nothing wrong with to much information! Be careful though as even A level barely scratches the surface where Microbiology is concerned!
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username3675004
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(Original post by Jaustin827)
Nothing wrong with to much information! Be careful though as even A level barely scratches the surface where Microbiology is concerned!
Well I’m planning to do medicine or biomedical science at uni, even though my bio teacher has somehow convinced himself I’m doing microbiology haha all I need now are 8/9s and 4 A*s......😭
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Jaustin827
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I'm starting Microbiology at in a few months! My best advice would be to start studying now and keep up with learning stuff because you want to and not just to do well in an exam!
Happy studying!
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username3675004
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(Original post by Jaustin827)
I'm starting Microbiology at in a few months! My best advice would be to start studying now and keep up with learning stuff because you want to and not just to do well in an exam!
Happy studying!
Thanks...have fun in microbiology!
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Jpw1097
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(Original post by 75324350)
Phew! Thanks for the whole para tho! I just feel that if I do get some question on HIV and I answer it like this that I won’t get full marks bc it is too high level and not actually in the mark scheme haha....I think biology is really interesting when you read about it, although I can barely pronounce half the words I’m reading for the A level stuff lol😂
Is the life cycle of HIV in your syllabus? I wouldn't worry too much about it at GCSE, so long as you get the general points. Your outline could apply to all viruses (virus glycoprotein binds to receptor on host cell, virus taken into cell via endocytosis, virus uncoats releasing its RNA/DNA genome and enzymes such as RNA-dependent RNA polymerase into the nucleus/cytoplasm, virus replicates and some viral mRNA is used to synthesise viral proteins, viral proteins and genome packaged into virion which is released from the cell via budding or lysing the cell). Some viruses contain RNA (e.g. HIV) while others contain DNA (e.g. herpes simplex virus, varicella zoster virus). DNA viruses tend to replicate in the nucleus using the host cell's own replicational machinery (i.e. DNA polymerase); RNA viruses on the other hand tend to replicate in the cytoplasm and therefore require their own polymerase (RNA-dependent RNA polymerase) as the human cells do not contain enzymes that can replicate RNA. Of course, there are always exceptions. Influenza, for example, an RNA virus, replicates within the host cell's nucleus.

Also, since you're interested in applying for medicine, as a second year medic myself, I would be more than happy to answer any questions regarding that.
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username3675004
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(Original post by Jpw1097)
Is the life cycle of HIV in your syllabus? I wouldn't worry too much about it at GCSE, so long as you get the general points. Your outline could apply to all viruses (virus glycoprotein binds to receptor on host cell, virus taken into cell via endocytosis, virus uncoats releasing its RNA/DNA genome and enzymes such as RNA-dependent RNA polymerase into the nucleus/cytoplasm, virus replicates and some viral mRNA is used to synthesise viral proteins, viral proteins and genome packaged into virion which is released from the cell via budding or lysing the cell). Some viruses contain RNA (e.g. HIV) while others contain DNA (e.g. herpes simplex virus, varicella zoster virus). DNA viruses tend to replicate in the nucleus using the host cell's own replicational machinery (i.e. DNA polymerase); RNA viruses on the other hand tend to replicate in the cytoplasm and therefore require their own polymerase (RNA-dependent RNA polymerase) as the human cells do not contain enzymes that can replicate RNA. Of course, there are always exceptions. Influenza, for example, an RNA virus, replicates within the host cell's nucleus.

Also, since you're interested in applying for medicine, as a second year medic myself, I would be more than happy to answer any questions regarding that.
Thank you! No idea if I even need to know this but it’s interesting and I’m bored so haha. Where are you doing medicine? And what A levels did you get?
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