3.2.4 HIV Flashcards Preview

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Flashcards in 3.2.4 HIV Deck (38)
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1

What is HIV?

Virus that affects immune system

2

What is AIDS?

Disease where immune system deteriorates & eventually fails

3

What cells do HIV infect and use as a host?

 helper T-cells

4

When are people said to have developed AIDS?

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

5

HIV has a ______ structure 

Spherical

6

What does HIV's core contain

RNA & proteins

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

7

What is HIV's outer coating of protein called?

Caspid

8

HIV has a ___ layer called an ______

HIV has a outer layer called an envelope

9

What is the envelope made out of?

Membrane stolen from cell membrane of previous host cell

10

What are sticking from the envelope?

Attachment proteins

(Contains glycoproteins)

11

What do attachment proteins help HIV to do?

To attach to host helper T-cell

12

What is a retrovirus (e.g. HIV)?

Use reverse transcriptase & RNA method

13

Describe how HIV replicates

  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

14

What happens during the initial infection period?

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

15

What happens after the initial infection period?

HIV replication drops to a lower level = latency period

16

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

Infected person won't experience any symptoms

17

What is the effect of AIDS?

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

18

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

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

19

Describe the initial symptoms of AIDS

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

20

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

Patients become susceptible to more serious infections

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

21

Describe the symptoms during the late stages of AIDS

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

22

Name an issue when trying diagnose HIV

Symptoms are non-specific

23

Name 2 ways of testing HIV

Blood tests

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

24

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

  • AIDS related symptoms 
  • No. of helper T cells 

25

Name 2 examples of treatments for HIV

  • Antiviral drugs
  • Enzyme inhibitors

26

What do antiviral drugs do?

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

27

Describe what an integrase inhibitor does

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

28

Describe what an attachment and entry inhibitor does

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

29

Describe what a protease inhibitor does

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

30

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

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

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