3.2.4 HIV Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is HIV?

A

Virus that affects immune system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is AIDS?

A

Disease where immune system deteriorates & eventually fails

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What cells do HIV infect and use as a host?

A

helper T-cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

When are people said to have developed AIDS?

A

When there’s less than 200 mm-3 helper T-cells numbers so body can’t fight usual harmless pathogens (e.g. flu)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

HIV has a ______ structure

A

Spherical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does HIV’s core contain

A

RNA & proteins

e.g. enzymes: reverse transcriptase, integrase, and protease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is HIV’s outer coating of protein called?

A

Caspid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

HIV has a ___ layer called an ______

A

HIV has a outer layer called an envelope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the envelope made out of?

A

Membrane stolen from cell membrane of previous host cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are sticking from the envelope?

A

Attachment proteins

(Contains glycoproteins)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do attachment proteins help HIV to do?

A

To attach to host helper T-cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a retrovirus (e.g. HIV)?

A

Use reverse transcriptase & RNA method

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe how HIV replicates

A
  1. Attachment protein attaches to CD4 cell-surface antigen on host helper T-cell
  2. Capsid is released into cell, where it uncoats and releases genetic material (viral RNA) & core proteins into cytoplasm
  3. Inside cell, reverse transcriptase is used to make complementary strand of DNA from viral RNA template
  4. From this, double-stranded viral DNA is made & inserted into human DNA
  5. Host cell enzymes are used to make viral proteins from viral DNA found within human DNA
  6. Viral proteins are assembled into new viruses (made by host cell), which bud from cell & go infect other cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens during the initial infection period?

A

HIV replicates rapidly & infected person may experience severe flu-like symptoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens after the initial infection period?

A

HIV replication drops to a lower level = latency period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What occurs during the latency period (which can last for years)?

A

Infected person won’t experience any symptoms

17
Q

What is the effect of AIDS?

A

Develop diseases that wouldn’t cause serious problems in people with healthy immune system

18
Q

Name 4 factors that affect the progression of HIV to AIDS & survival time with AIDS

A
  1. Existing infections
  2. Strain of HIV
  3. Age
  4. Access to healthcare
19
Q

Describe the initial symptoms of AIDS

A

Minor infection of mucous membranes (e.g. inside of nose, ears) & recurring respiratory infections

20
Q

Describe the symptoms of as AIDS progress & as no. of immune system cells decrease

A

Patients become susceptible to more serious infections

e.g. chronic diarrhoea, severe bacterial infections, tuberculosis

21
Q

Describe the symptoms during the late stages of AIDS

A
  • Can develop range of serious infections
  • These kill AIDS patients not HIV itself
22
Q

Name an issue when trying diagnose HIV

A

Symptoms are non-specific

23
Q

Name 2 ways of testing HIV

A

Blood tests

  • Antibodies to HIV
  • Looking for HIV specific protein - P24
24
Q

When diagnosing AIDS, what do you need to look at? (2)

A
  • AIDS related symptoms
  • No. of helper T cells
25
Q

Name 2 examples of treatments for HIV

A
  • Antiviral drugs
  • Enzyme inhibitors
26
Q

What do antiviral drugs do?

A

Slow down the progression of HIV infection and AIDS in an infected person

27
Q

Describe what an integrase inhibitor does

A

Binds to integrase so viral DNA can’t be transcribed so viral RNA and proteins cannot be produced

28
Q

Describe what an attachment and entry inhibitor does

A
  • During attachment, protein on HIV binds to CD4 receptors
  • Attachment and entry inhibitors bind to these attachment points
29
Q

Describe what a protease inhibitor does

A

Prevents protease catalysing the assembly of viral proteins in cytoplasm of host

30
Q

Name 3 reasons why HIV vaccinations are considered unsafe (3)

A
  • Inactive virus may become active
  • Protein from HIV may harm cells
  • People may test HIV positive after vaccine used
31
Q

How do antibiotics kill bacteria?

A
  • Interfer with their metabolic reactions
    • Target bacterial enzymes and ribosomes used in these reactions
32
Q

Why can antibiotics only target bacterial enzymes & ribosomes, and thus not damage human cells?

A

Bacterial enzymes & ribosomes are different from human enzymes & ribosomes

33
Q

Why can’t antibiotics be used to cure viruses?

A

Don’t have their own enzymes & ribosomes (use host cells’ ones)

34
Q

What do most antiviral drugs do?

A

Target few virus-specific enzymes

e.g. HIV uses revere transcriptase to replicate ∴ prevented by using reverse-transcriptase inhibitors

35
Q

Name 3 ways HIV spreads

A
  • Unprotected sexual intercourse
  • Infected bodily fluids
    • (e.g. like blood from sharing contaminated needles)
  • From HIV-postive mother to her fetus
36
Q

Not all babies are born infected with HIV & taking ____ _____ during pregnancy can reduce chance of baby being HIV-positive

A

antiviral drugs

37
Q

Why is HIV testing, based on HIV antibody detection, before a baby is 18 months inaccurate?

A

∵ baby of HIV-positive mother may have some HIV antibodies in their blood regardless of whether or not they’re infected

38
Q

When can a virus be described as inactive?

A

When it’s not replicating