May/June 2017
QUESTION 1
What is currently the most widely accepted scientific theory about the origin of Aids?
1. an ancestor of HIV-1 group M virus was transmitted from a chimpanzee to a hunter
2. HIV was introduced into the human population by polio vaccines which were produced on monkey
kidney cell cultures in the 1950s
3. Aids is not a new disease, but has probably been present for many centuries in central Africa
4. HIV originated in the white gay communities of America and Europe in the early 1980s
QUESTION 2
We know how many people are infected with HIV by looking at the HIV incidence and the HIV
prevalence What is the definition of HIV prevalence?
1. It is the percentage of people living with HIV (as a proportion of the total population) at a specific time
2. It is a snapshot view of the number of people who were infected with HIV in a specific year in the past 5
years
3. It is the percentage of new cases of HIV infection in a defined period of time, for example in one year
4. It is a percentage which is calculated by dividing the number of new infections by the number of
previously uninfected people.
QUESTION 3
How do viruses (including HIV) reproduce?
1. Viruses can reproduce in any warm and humid environment, the cells of the virus divide to form new
viruses
2. Viruses reproduce in the open air, they cannot reproduce in anaerobic conditions
3. Viruses inject their genetic material into a living cell and then use the cell to reproduce more viruses
4. Viruses first kill cells, then enter them and then use the remains of the cell as food' for the new viruses
QUESTION 4
How do the dendritic cells warn the lymphocytes (B and Tcells) that they should mobilise to
protect the body against an organic invader such as a virus? The dendritic cells
1. swailow the virus and then carry it to the lymphocytes, which then destroy both the dendritic cells and
the virus
2. surround the virus, grab an antigen from it and display it like a banner of war in order to mobilise the
lymphocytes
3. surround the virus and render it inactive until the lymphocytes find it and kill it
4. swallow the virus and, when the dendritic cells die, the virus dies with them, thus warning lymphocytes
about the presence of the foreign antigens in the process
QUESTION 1
What is currently the most widely accepted scientific theory about the origin of Aids?
1. an ancestor of HIV-1 group M virus was transmitted from a chimpanzee to a hunter
2. HIV was introduced into the human population by polio vaccines which were produced on monkey
kidney cell cultures in the 1950s
3. Aids is not a new disease, but has probably been present for many centuries in central Africa
4. HIV originated in the white gay communities of America and Europe in the early 1980s
QUESTION 2
We know how many people are infected with HIV by looking at the HIV incidence and the HIV
prevalence What is the definition of HIV prevalence?
1. It is the percentage of people living with HIV (as a proportion of the total population) at a specific time
2. It is a snapshot view of the number of people who were infected with HIV in a specific year in the past 5
years
3. It is the percentage of new cases of HIV infection in a defined period of time, for example in one year
4. It is a percentage which is calculated by dividing the number of new infections by the number of
previously uninfected people.
QUESTION 3
How do viruses (including HIV) reproduce?
1. Viruses can reproduce in any warm and humid environment, the cells of the virus divide to form new
viruses
2. Viruses reproduce in the open air, they cannot reproduce in anaerobic conditions
3. Viruses inject their genetic material into a living cell and then use the cell to reproduce more viruses
4. Viruses first kill cells, then enter them and then use the remains of the cell as food' for the new viruses
QUESTION 4
How do the dendritic cells warn the lymphocytes (B and Tcells) that they should mobilise to
protect the body against an organic invader such as a virus? The dendritic cells
1. swailow the virus and then carry it to the lymphocytes, which then destroy both the dendritic cells and
the virus
2. surround the virus, grab an antigen from it and display it like a banner of war in order to mobilise the
lymphocytes
3. surround the virus and render it inactive until the lymphocytes find it and kill it
4. swallow the virus and, when the dendritic cells die, the virus dies with them, thus warning lymphocytes
about the presence of the foreign antigens in the process
