HIV/AIDS

Question 1

What does HIV stand for?

Answer 1

Human immunodeficiency virus

Question 2

What proteins does HIV contain?

Answer 2

Enzyme - reverse transcriptase

Question 3

What type of virus is HIV?

Answer 3

Retrovirus

Question 4

What is a retrovirus?

Answer 4

A virus that uses reverse transcription

Question 5

What type of genetic material does HIV contain?

Answer 5

Double stranded mRNA

Question 6

What type of attachment proteins does HIV have?

Answer 6

Glycoproteins

Question 7

What type of envelope does HIV have?

Answer 7

Lipid bilayer envelope

Question 8

How does HIV weaken the immune system?

Answer 8

• Destroys T helper cells
• These activate other immune system cells
• Weakens overall immune system

Question 9

Why do HIV cells invade T helper cells?

Answer 9

To use the organelles of the host cell to reproduce e.g ribosomes

Question 10

What are the attachment proteins on HIV called?

Answer 10

GP120 molecules

Question 11

What are the receptors on T helper cells called?

Answer 11

CD4 receptors

Question 12

Describe how HIV invades T helper cells

Answer 12

• Attachment proteins, GP120, on the virus surface bind to CD4 receptors on T helper cell surface membranes
• Virus envelope fuses with T helper cell surface membrane
• Capsid released into cell
• Uncoats and releases genetic material into host cell cytoplasm
• Reverse transciptase used to make complementary strand of DNA from viral template
• Double stranded DNA made inserted into host cell human DNA with enzyme integrase
• Host cell transcribes and translates viral DNA to make viral protein
• Viral proteins assembled into new viruses
• New viruses burst from host cell in lysis to infect other cells
• Take from the host cell surface membrane

Question 13

What are the consequences of HIV infecting T helper cells? 4

Answer 13

• Infected T helper cells destroyed by T killer cells
• More HIV replicates rapidly so T helper cells decrease rapidly
• Person has severe flu like symptoms
• HIV replication drops to a lower level : latency period

Question 14

What is the HIV latency period? 3

Answer 14

• HIV replication drops to low level
• Person infected with HIV has no obvious symptoms but increased tendency to develop colds and mild infections
• Can last several years

Question 15

What can keep a person in the HIV latency period? 2

Answer 15

Healthy lifestyle and drugs

Question 16

What does AIDS stand for?

Answer 16

Acquired Immune Deficiency Syndrome

Question 17

What happens in AIDS? 2

Answer 17

• Immune system deteriorates and eventually fails
• As macrophages, B cells and T killer cells not successfully activated by T helper cells so no longer functioning properly

Question 18

Why does HIV develop to AIDS in developing countries? 2

Answer 18

• Little money for drugs

- No access to sufficient food/clean water

Question 19

When is a person infected with HIV classed as suffering from AIDS?

Answer 19

When their T helper cells falls below a certain count

Question 20

What do people with AIDS suffer from?

Answer 20

Opportunistic infections - diseases/infections not causing problems in healthy immune systems

Question 21

Give 2 examples of opportunistic infections

Answer 21

• TB

- Pneumonia

Question 22

What are the factors affecting the progression of HIV to AIDS and survival time of those with AIDS? 4

Answer 22

• Age
• Existing infections
• Access to healthcare
• Strain of HIV

Question 23

Give 4 ways AIDS can be transmitted

Answer 23

Contact of infected bodily fluids:

• Unprotected sex
• Sharing needles
• Breastmilk - maternal transmission
• Blood to blood transfer e.g through cuts

Question 24

How can HIV be treated?

Answer 24

• Antiretroviral drugs - reverse transcriptase inhibitors

- So they reduce production of more viruses