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SAJID A Level AQA Biology > 5.7: Human immunodeficiency virus (HIV) > Flashcards

5.7: Human immunodeficiency virus (HIV) Flashcards

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1
Q

The human immunodeficiency virus (HIV) causes the disease acquired immune deficiency syndrome (AIDS).
Among contagious diseases, it is a relative newcomer, having first been diagnosed when?

A

Among contagious diseases, AIDS is a relative newcomer, having first been diagnosed in 1981

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2
Q

The structure of HIV:

What is on the outside?

A

On the outside is a lipid envelope

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3
Q

The structure of HIV:

On the outside is a lipid envelope, embedded in which are what?

A

On the outside is a lipid envelope, embedded in which are peg-like attachment proteins

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4
Q

The structure of HIV:
On the outside is a lipid envelope, embedded in which are peg-like attachment proteins.
What is there inside the lipid envelope?

A

Inside the lipid envelope there is a protein layer called the capsid

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5
Q

The structure of HIV:
On the outside is a lipid envelope, embedded in which are peg-like attachment proteins.
Inside the lipid envelope there is a protein layer called the capsid that does what?

A

Inside the lipid envelope there is a protein layer called the capsid that encloses:

  1. 2 single strands of RNA
  2. Some enzymes
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6
Q

The structure of HIV:
On the outside is a lipid envelope, embedded in which are peg-like attachment proteins.
Inside the lipid envelope there is a protein layer called the capsid that encloses 2 single strands of DNA and some enzymes.
What is one of these enzymes?

A

One of these enzymes is reverse transcriptase

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7
Q

The structure of HIV:
On the outside is a lipid envelope, embedded in which are peg-like attachment proteins.
Inside the lipid envelope there is a protein layer called the capsid that encloses 2 single strands of DNA and some enzymes.
One of these enzymes is reverse transcriptase, so-called because it does what?

A

One of these enzymes is reverse transcriptase, so-called because it catalyses the production of DNA from RNA

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8
Q

The structure of HIV:
On the outside is a lipid envelope, embedded in which are peg-like attachment proteins.
Inside the lipid envelope there is a protein layer called the capsid that encloses 2 single strands of DNA and some enzymes.
One of these enzymes is reverse transcriptase, so-called because it catalyses the production of DNA from RNA - The reverse reaction to what?

A

One of these enzymes is reverse transcriptase, so-called because it catalyses the production of DNA from RNA - The reverse reaction to that carried out by transcriptase

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9
Q

The structure of HIV:
On the outside is a lipid envelope, embedded in which are peg-like attachment proteins.
Inside the lipid envelope there is a protein layer called the capsid that encloses 2 single strands of DNA and some enzymes.
One of these enzymes is reverse transcriptase, so-called because it catalyses the production of DNA from RNA - The reverse reaction to that carried out by transcriptase.
The presence of reverse transcriptase, and consequent ability to do what, means that HIV belongs to a group of viruses called what?

A
  1. The presence of reverse transcriptase
  2. Consequent ability to make DNA from RNA
    ,means that HIV belongs to a group of viruses called retroviruses
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10
Q

HIV replication:

Being a virus, HIV cannot do what?

A

Being a virus, HIV cannot replicate itself

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11
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
What is the genetical material in HIV?

A

The genetic material in HIV is RNA

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12
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
The genetic material in HIV is RNA.
What does RNA use?

A

RNA uses reverse transcriptase

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13
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which does what?

A

Reverse transcriptase is an enzyme which:

  1. Takes the viral RNA
  2. Copies it to make DNA
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14
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which takes the viral DNA and copies it to make DNA.
In this way, what can the virus do?

A

In this way, the virus can insert DNA made from its RNA into the human genome

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15
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which takes the viral DNA and copies it to make DNA.
In this way, the virus can insert DNA made from its RNA into the human genome.
The DNA copies of the virus RNA is what by an enzyme called what?

A

The DNA copies of the virus RNA is spliced into the host’s DNA by an enzyme called integrase

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16
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, what does HIV do?

A

Following infection, HIV:

  1. Enters the bloodstream
  2. Circulates around the body
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17
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
What readily binds to what?

A

A protein on the HIV readily binds to a protein called CD4

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18
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, what does HIV attach most frequently to?

A

While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells

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19
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
What fuses with the cell-surface membrane?

A

The protein capsid fuses with the cell-surface membrane

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20
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
What enter the T helper cell?

A

The:
1. RNA
2. Enzymes
of HIV enter the T helper cell

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21
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
The RNA and enzymes of HIV enter the T helper cell.
What is the genetic material in HIV?

A

The genetic material in HIV is RNA

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22
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
The RNA and enzymes of HIV enter the T helper cell.
The genetic material in HIV is RNA.
What does RNA use?

A

RNA uses reverse transcriptase

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23
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
The RNA and enzymes of HIV enter the T helper cell.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which does what?

A

Reverse transcriptase is an enzyme which:

  1. Takes the viral DNA
  2. Copies it to make DNA
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24
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
The RNA and enzymes of HIV enter the T helper cell.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which takes the viral DNA and copies it to make DNA.
In this way, what can the virus do?

A

In this way, the virus can insert DNA made from its RNA into the human genome

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25
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
The RNA and enzymes of HIV enter the T helper cell.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which takes the viral DNA and copies it to make DNA.
In this way, the virus can insert DNA made from its RNA into the human genome.
What does the HIV reverse transcriptase do?

A

The HIV reverse transcriptase converts the virus’ RNA into DNA

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26
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
The RNA and enzymes of HIV enter the T helper cell.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which takes the viral DNA and copies it to make DNA.
In this way, the virus can insert DNA made from its RNA into the human genome.
The HIV reverse transcriptase converts the virus’ RNA into DNA.
What happens by an enzyme called integrase?

A

The DNA copies of the virus RNA is spliced into the host’s DNA by an enzyme called integrase

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27
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
The RNA and enzymes of HIV enter the T helper cell.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which takes the viral DNA and copies it to make DNA.
In this way, the virus can insert DNA made from its RNA into the human genome.
The HIV reverse transcriptase converts the virus’ RNA into DNA.
The DNA copies of the virus RNA is spliced into the host’s DNA by an enzyme called integrase.
What happens to the newly made DNA?

A

The newly made DNA is moved into the helper T cell’s nucleus

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28
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
The RNA and enzymes of HIV enter the T helper cell.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which takes the viral DNA and copies it to make DNA.
In this way, the virus can insert DNA made from its RNA into the human genome.
The HIV reverse transcriptase converts the virus’ RNA into DNA.
The DNA copies of the virus RNA is spliced into the host’s DNA by an enzyme called integrase.
The newly made DNA is moved into the helper T cell’s nucleus, where it is what?

A

The newly made DNA is moved into the helper T cell’s nucleus, where it is inserted into the cell’s DNA

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29
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
The RNA and enzymes of HIV enter the T helper cell.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which takes the viral DNA and copies it to make DNA.
In this way, the virus can insert DNA made from its RNA into the human genome.
The HIV reverse transcriptase converts the virus’ RNA into DNA.
The DNA copies of the virus RNA is spliced into the host’s DNA by an enzyme called integrase.
The newly made DNA is moved into the helper T cell’s nucleus, where it is inserted into the cell’s DNA.
The HIV DNA in the nucleus creates what?

A

The HIV DNA in the nucleus creates messenger RNA (mRNA)

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30
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
The RNA and enzymes of HIV enter the T helper cell.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which takes the viral DNA and copies it to make DNA.
In this way, the virus can insert DNA made from its RNA into the human genome.
The HIV reverse transcriptase converts the virus’ RNA into DNA.
The DNA copies of the virus RNA is spliced into the host’s DNA by an enzyme called integrase.
The newly made DNA is moved into the helper T cell’s nucleus, where it is inserted into the cell’s DNA.
The HIV DNA in the nucleus creates messenger RNA (mRNA), using what?

A

The HIV DNA in the nucleus creates messenger RNA (mRNA), using the cell’s enzymes

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31
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
The RNA and enzymes of HIV enter the T helper cell.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which takes the viral DNA and copies it to make DNA.
In this way, the virus can insert DNA made from its RNA into the human genome.
The HIV reverse transcriptase converts the virus’ RNA into DNA.
The DNA copies of the virus RNA is spliced into the host’s DNA by an enzyme called integrase.
The newly made DNA is moved into the helper T cell’s nucleus, where it is inserted into the cell’s DNA.
The HIV DNA in the nucleus creates messenger RNA (mRNA), using the cell’s enzymes.
This mRNA contains the instructions for doing what?

A

This mRNA contains the instructions for making new:
1. Viral proteins
2. The RNA
to go into the new HIV

32
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
The RNA and enzymes of HIV enter the T helper cell.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which takes the viral DNA and copies it to make DNA.
In this way, the virus can insert DNA made from its RNA into the human genome.
The HIV reverse transcriptase converts the virus’ RNA into DNA.
The DNA copies of the virus RNA is spliced into the host’s DNA by an enzyme called integrase.
The newly made DNA is moved into the helper T cell’s nucleus, where it is inserted into the cell’s DNA.
The HIV DNA in the nucleus creates messenger RNA (mRNA), using the cell’s enzymes.
This mRNA contains the instructions for making new viral proteins and the RNA to go into the new HIV.
The mRNA passes out of the nucleus through what?

A

The mRNA passes out of the nucleus through a nuclear pore

33
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
The RNA and enzymes of HIV enter the T helper cell.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which takes the viral DNA and copies it to make DNA.
In this way, the virus can insert DNA made from its RNA into the human genome.
The HIV reverse transcriptase converts the virus’ RNA into DNA.
The DNA copies of the virus RNA is spliced into the host’s DNA by an enzyme called integrase.
The newly made DNA is moved into the helper T cell’s nucleus, where it is inserted into the cell’s DNA.
The HIV DNA in the nucleus creates messenger RNA (mRNA), using the cell’s enzymes.
This mRNA contains the instructions for making new viral proteins and the RNA to go into the new HIV.
The mRNA passes out of the nucleus through a nuclear pore and uses the cell’s what mechanisms to make HIV particles?

A

The mRNA:

  1. Passes out of the nucleus through a nuclear pore
  2. Uses the cell’s protein synthesis mechanisms to make HIV particles
34
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
The RNA and enzymes of HIV enter the T helper cell.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which takes the viral DNA and copies it to make DNA.
In this way, the virus can insert DNA made from its RNA into the human genome.
The HIV reverse transcriptase converts the virus’ RNA into DNA.
The DNA copies of the virus RNA is spliced into the host’s DNA by an enzyme called integrase.
The newly made DNA is moved into the helper T cell’s nucleus, where it is inserted into the cell’s DNA.
The HIV DNA in the nucleus creates messenger RNA (mRNA), using the cell’s enzymes.
This mRNA contains the instructions for making new viral proteins and the RNA to go into the new HIV.
The mRNA passes out of the nucleus through a nuclear pore and uses the cell’s protein synthesis mechanisms to make HIV particles.
What are assembled together and new viruses are made?

A 
The:
1. Proteins
2. Viral RNA
3. Glycoproteins
are assembled together and new viruses are made
35
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
The RNA and enzymes of HIV enter the T helper cell.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which takes the viral DNA and copies it to make DNA.
In this way, the virus can insert DNA made from its RNA into the human genome.
The HIV reverse transcriptase converts the virus’ RNA into DNA.
The DNA copies of the virus RNA is spliced into the host’s DNA by an enzyme called integrase.
The newly made DNA is moved into the helper T cell’s nucleus, where it is inserted into the cell’s DNA.
The HIV DNA in the nucleus creates messenger RNA (mRNA), using the cell’s enzymes.
This mRNA contains the instructions for making new viral proteins and the RNA to go into the new HIV.
The mRNA passes out of the nucleus through a nuclear pore and uses the cell’s protein synthesis mechanisms to make HIV particles.
The proteins, viral RNA and glycoproteins are assembled together and new viruses are made.
The HIV particles break away from the T helper cell, taking what as what?

A

The HIV particles break away from the T helper cell, taking host lipids from the host cell-surface membrane surrounding them as a viral coat

36
Q

HIV replication:
Being a virus, HIV cannot replicate itself.
Instead HIV uses its genetic material to instruct the host cell’s biochemical mechanisms to produce the components required to make new HIV.
It does so as follows:
Following infection, HIV enters the bloodstream and circulates around the body.
A protein on the HIV readily binds to a protein called CD4.
While this protein occurs on a number of different cells, HIV attaches most frequently to T helper cells.
The protein capsid fuses with the cell-surface membrane.
The RNA and enzymes of HIV enter the T helper cell.
The genetic material in HIV is RNA.
RNA uses reverse transcriptase.
Reverse transcriptase is an enzyme which takes the viral DNA and copies it to make DNA.
In this way, the virus can insert DNA made from its RNA into the human genome.
The HIV reverse transcriptase converts the virus’ RNA into DNA.
The DNA copies of the virus RNA is spliced into the host’s DNA by an enzyme called integrase.
The newly made DNA is moved into the helper T cell’s nucleus, where it is inserted into the cell’s DNA.
The HIV DNA in the nucleus creates messenger RNA (mRNA), using the cell’s enzymes.
This mRNA contains the instructions for making new viral proteins and the RNA to go into the new HIV.
The mRNA passes out of the nucleus through a nuclear pore and uses the cell’s protein synthesis mechanisms to make HIV particles.
The proteins, viral RNA and glycoproteins are assembled together and new viruses are made.
The HIV particles break away from the T helper cell, taking host lipids from the host cell-surface membrane surrounding them as a viral coat.
Why does this help to protect them?

A

This helps to protect them, because they kill the T helper cell as they leave

37
Q

Once infected with HIV, a person is said to be HIV positive.

However, what does the replication of HIV often do?

A

The replication of HIV often goes into dormancy

38
Q

Once infected with HIV, a person is said to be HIV positive.

However, the replication of HIV often goes into dormancy and only recommences, leading to AIDS, when?

A

The replication of HIV:

  1. Often goes into dormancy
  2. Only recommences, leading to AIDS, many years later
39
Q

How HIV causes the symptoms of AIDS:

What does the human immunodeficiency virus (HIV) specifically do?

A

The human immunodeficiency virus (HIV) specifically attacks T helper cells

40
Q

How HIV causes the symptoms of AIDS:
The human immunodeficiency virus (HIV) specifically attacks T helper cells.
The HIV causes AIDS by killing or interfering with what?

A 
The HIV causes AIDS by:
1. Killing
Or,
2. Interfering with
the normal functioning of T helper cells
41
Q

How HIV causes the symptoms of AIDS:
The human immunodeficiency virus (HIV) specifically attacks T helper cells.
The HIV causes AIDS by killing or interfering with the normal functioning of T helper cells.
T helper cells are important in cell-mediated immunity.
Without a sufficient number of T helper cells, the immune system cannot do what?

A

Without a sufficient number of T helper cells, the immune system cannot stimulate B cells to produce:
1. Antibodies
Or,
2. The cytotoxic T cells that kill cells infected by pathogens

42
Q

How HIV causes the symptoms of AIDS:
The human immunodeficiency virus (HIV) specifically attacks T helper cells.
The HIV causes AIDS by killing or interfering with the normal functioning of T helper cells.
T helper cells are important in cell-mediated immunity.
Without a sufficient number of T helper cells, the immune system cannot stimulate B cells to produce antibodies or the cytotoxic T cells that kill cells infected by pathogens.
What may also become infected and destroyed?

A

Memory cells may also become:

  1. Infected
  2. Destroyed
43
Q

How HIV causes the symptoms of AIDS:
The human immunodeficiency virus (HIV) specifically attacks T helper cells.
The HIV causes AIDS by killing or interfering with the normal functioning of T helper cells.
T helper cells are important in cell-mediated immunity.
Without a sufficient number of T helper cells, the immune system cannot stimulate B cells to produce antibodies or the cytotoxic T cells that kill cells infected by pathogens.
Memory cells may also become infected and destroyed.
As a result, the body what?

A

As a result, the body:

  1. Is unable to produce an adequate immune response
  2. Becomes susceptible to other infections and cancers
44
Q

How HIV causes the symptoms of AIDS:
The human immunodeficiency virus (HIV) specifically attacks T helper cells.
The HIV causes AIDS by killing or interfering with the normal functioning of T helper cells.
T helper cells are important in cell-mediated immunity.
Without a sufficient number of T helper cells, the immune system cannot stimulate B cells to produce antibodies or the cytotoxic T cells that kill cells infected by pathogens.
Memory cells may also become infected and destroyed.
As a result, the body in unable to produce an adequate immune response and becomes susceptible to other infections and cancers.
Many AIDS sufferers develop infections of the lungs, intestines, brain and eyes, as well as experiencing weight loss and diarrhoea.
It is these secondary diseases that ultimately do what?

A

It is these secondary diseases that ultimately cause death

45
Q

How HIV causes the symptoms of AIDS:
Infected T helper cells can be killed by T killer cells.
This together with the T helper cells being destroyed when the virus leaves drastically does what?

A

This together with the T helper cells being destroyed when the virus leaves drastically reduces the T helper cells available

46
Q

How HIV causes the symptoms of AIDS:
Infected T helper cells can be killed by T killer cells.
This together with the T helper cells being destroyed when the virus leaves drastically reduces the T helper cells available.
The loss of T helper cells means that what will not be activated?

A 
The loss of T helper cells means that:
1. Macrophages
2. T killer cells
3. B cells
will not be activated
47
Q

How HIV causes the symptoms of AIDS:
Infected T helper cells can be killed by T killer cells.
This together with the T helper cells being destroyed when the virus leaves drastically reduces the T helper cells available.
The loss of T helper cells means that macrophages, T killer cells and B cells will not be activated.
The person’s immune system will be what?

A

The person’s immune system will be seriously impaired

48
Q

Antibiotics work in a number of different ways.

One is preventing bacteria from doing what?

A

One is preventing bacteria from making normal cell walls

49
Q

Antibiotics work in a number of different ways.
One is preventing bacteria from making normal cell walls.
In bacterial cells, as in plant cells, water constantly does what by osmosis?

A

In bacterial cells, as in plant cells, water constantly enters by osmosis

50
Q

Antibiotics work in a number of different ways.
One is preventing bacteria from making normal cell walls.
In bacterial cells, as in plant cells, water constantly enters by osmosis.
This entry of water would normally cause the cell to burst.
That it doesn’t burst is due to the wall that surrounds all bacterial cells.
This wall is made of murein, a tough material that is not what?

A

This wall is made of murein, a tough material that is not easily stretched

51
Q

Antibiotics work in a number of different ways.
One is preventing bacteria from making normal cell walls.
In bacterial cells, as in plant cells, water constantly enters by osmosis.
This entry of water would normally cause the cell to burst.
That it doesn’t burst is due to the wall that surrounds all bacterial cells.
This wall is made of murein, a tough material that is not easily stretched.
As water enters the cell by osmosis, the cell expands and pushes against the cell wall.
Being relatively inelastic, the cell wall resists expansion and so halts further entry of water.
What do antibiotics like penicillin inhibit?

A

Antibiotics like penicillin inhibit certain enzymes required for the:
1. Synthesis
2. Assembly
of the peptide cross-linkages in bacterial cell walls

52
Q

Antibiotics work in a number of different ways.
One is preventing bacteria from making normal cell walls.
In bacterial cells, as in plant cells, water constantly enters by osmosis.
This entry of water would normally cause the cell to burst.
That it doesn’t burst is due to the wall that surrounds all bacterial cells.
This wall is made of murein, a tough material that is not easily stretched.
As water enters the cell by osmosis, the cell expands and pushes against the cell wall.
Being relatively inelastic, the cell wall resists expansion and so halts further entry of water.
Antibiotics like penicillin inhibit certain enzymes required for the synthesis and assembly of the peptide cross-linkages in bacterial cell walls.
This weakens the walls, making them unable to withstand pressure.
As water enters naturally by osmosis, what happens?

A

As water enters naturally by osmosis, the:

  1. Cell bursts
  2. Bacterium dies
53
Q

Why antibiotics are ineffective against viral diseases like AIDS:
Viruses rely on the host cells to do what?

A

Viruses rely on the host cells to carry out their metabolic activities

54
Q

Why antibiotics are ineffective against viral diseases like AIDS:
Viruses rely on the host cells to carry out their metabolic activities and therefore lack what?

A

Viruses rely on the host cells to carry out their metabolic activities and therefore lack their own:

  1. Metabolic pathways
  2. Cell structures
55
Q

Why antibiotics are ineffective against viral diseases like AIDS:
Viruses rely on the host cells to carry out their metabolic activities and therefore lack their own metabolic pathways and cell structures.
As a result, why are antibiotics ineffective?

A 
As a result, antibiotics are ineffective, because there are no:
1. Metabolic mechanisms
Or,
2. Cell structures
for them to disrupt
56
Q

Why antibiotics are ineffective against viral diseases like AIDS:
Viruses rely on the host cells to carry out their metabolic activities and therefore lack their own metabolic pathways and cell structures.
As a result, antibiotics are ineffective, because there are no metabolic mechanisms or cell structures for them to disrupt.
Viruses also have what rather than a murein cell wall?

A

Viruses also have a:
1. Protein coat
rather than
2. Murein cell wall

57
Q

Why antibiotics are ineffective against viral diseases like AIDS:
Viruses rely on the host cells to carry out their metabolic activities and therefore lack their own metabolic pathways and cell structures.
As a result, antibiotics are ineffective, because there are no metabolic mechanisms or cell structures for them to disrupt.
Viruses also have a protein coat rather than a murein cell wall and so do not have what?

A

Viruses:

  1. Also have a protein coat rather than a murein cell wall
  2. So do not have sites where antibiotics can work
58
Q

Why antibiotics are ineffective against viral diseases like AIDS:
Viruses rely on the host cells to carry out their metabolic activities and therefore lack their own metabolic pathways and cell structures.
As a result, antibiotics are ineffective, because there are no metabolic mechanisms or cell structures for them to disrupt.
Viruses also have a protein coat rather than a murein cell wall and so do not have sites where antibiotics can work.
In any case, when viruses are within an organism’s own cells, what?

A

In any case, when viruses are within an organism’s own cells, antibiotics cannot reach them

59
Q

The course of a HIV infection:
Stage 1 - Acute HIV syndrome:
After how long, what are found in the blood?

A

After 3 - 12 weeks, HIV antibodies are found in the blood

60
Q

The course of a HIV infection:
Stage 1 - Acute HIV syndrome:
After 3 - 12 weeks, HIV antibodies are found in the blood.
The person may experience what?

A

The person may experience symptoms of an infection

61
Q

The course of a HIV infection:
Stage 1 - Acute HIV syndrome:
After 3 - 12 weeks, HIV antibodies are found in the blood.
The person may experience symptoms of an infection, for example what?

A

The person may experience symptoms of an infection, for example:

  1. Swollen glands
  2. A fever
62
Q

The course of a HIV infection:
Stage 1 - Acute HIV syndrome:
After 3 - 12 weeks, HIV antibodies are found in the blood.
The person may experience symptoms of an infection, for example swollen glands and a fever.
Sometimes there are no what?

A

Sometimes there are no symptoms

63
Q

The course of a HIV infection:
Stage 1 - Acute HIV syndrome:
After 3 - 12 weeks, HIV antibodies are found in the blood.
The person may experience symptoms of an infection, for example swollen glands and a fever.
Sometimes there are no symptoms.
There is a loss of T helper cells.
After a while, what happens?

A

After a while, the infected T helper cells are killed by T killer cells

64
Q

The course of a HIV infection:
Stage 1 - Acute HIV syndrome:
After 3 - 12 weeks, HIV antibodies are found in the blood.
The person may experience symptoms of an infection, for example swollen glands and a fever.
Sometimes there are no symptoms.
There is a loss of T helper cells.
After a while, the infected T helper cells are killed by T killer cells.
What does this do?

A

This:
1. Reduces the rate of the virus replication
,but
2. Does not stop it

65
Q

The course of a HIV infection:
Stage 2 - The chronic phase:
What will disappear?

A

All symptoms will disappear

66
Q

The course of a HIV infection:
Stage 2 - The chronic phase:
All symptoms will disappear, as what happens?

A

All symptoms will disappear, as T killer cells kill off infected CD4 T helper cells

67
Q

The course of a HIV infection:
Stage 2 - The chronic phase:
All symptoms will disappear, as T killer cells kill off infected CD4 T helper cells.
This can last for up to 6 years in what people?

A

This can last for up to 6 years in:
1. Fit
2. Healthy
people

68
Q

The course of a HIV infection:
Stage 2 - The chronic phase:
All symptoms will disappear, as T killer cells kill off infected CD4 T helper cells.
This can last for up to 6 years in fit, healthy people.
What increases?

A

A gradual tendency for susceptibility to diseases increases

69
Q

The course of a HIV infection:
Stage 2 - The chronic phase:
All symptoms will disappear, as T killer cells kill off infected CD4 T helper cells.
This can last for up to 6 years in fit, healthy people.
A gradual tendency for susceptibility to diseases increases.
There can be what?

A

There can be a reactivation of dormant diseases

70
Q

The course of a HIV infection:
Stage 2 - The chronic phase:
All symptoms will disappear, as T killer cells kill off infected CD4 T helper cells.
This can last for up to 6 years in fit, healthy people.
A gradual tendency for susceptibility to diseases increases.
There can be a reactivation of dormant diseases, like what?

A

There can be a reactivation of dormant diseases, like:

  1. TB
  2. Shingles
71
Q

The course of a HIV infection:
Stage 3 - The disease stage:
The viral load becomes so great that the T helper level falls to below half it’s normal level.
Patients suffer what?

A

Patients suffer AIDS

72
Q

The course of a HIV infection:
Stage 3 - The disease stage:
The viral load becomes so great that the T helper level falls to below half it’s normal level.
Patients suffer AIDS and related symptoms such as what?

A

Patients suffer:

  1. AIDS
  2. Related symptoms such as weight loss, fatigue and night sweats
73
Q

The course of a HIV infection:
Stage 4 - Advanced AIDS:
The immune system is so low that what?

A

The immune system is so low that ‘opportunistic infections’ can take hold

74
Q

The course of a HIV infection:
Stage 4 - Advanced AIDS:
The immune system is so low that ‘opportunistic infections’ can take hold.
What are these?

A

These are diseases like:

  1. Pneumonia
  2. Meningitis
  3. TB
75
Q

The course of a HIV infection:
Stage 4 - Advanced AIDS:
The immune system is so low that ‘opportunistic infections’ can take hold.
These are diseases like pneumonia, meningitis and TB.
Patients also have a tendency to develop purple/black patches on the skin caused by a cancer called what?

A

Patients also have a tendency to develop purple/black patches on the skin caused by a cancer called Karposi’s sarcoma

76
Q

The course of a HIV infection:
Stage 4 - Advanced AIDS:
The immune system is so low that ‘opportunistic infections’ can take hold.
These are diseases like pneumonia, meningitis and TB.
Patients also have a tendency to develop purple/black patches on the skin caused by a cancer called Karposi’s sarcoma.
There is significant weight loss.
Patients can suffer dementia, as what?

A

Patients can suffer dementia, as the AIDS virus can invade macrophages that can cross the brain-blood barrier

SAJID A Level AQA Biology (69 decks)

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