Diseases and ImmunityCambridge IGCSE Biology: Topic test

20 questions, 54 marks

Cambridge IGCSE Biology

Diseases and Immunity topic test

Total 54 marks

Name

Class

Date

1
A school nurse explained to students that a stomach bug spreading through a boarding house was being passed between students who shared cutlery and cups, and was also spreading through contact with surfaces that an infected student had touched, such as door handles.
(a)
What is a pathogen?
[1 mark]
Aa disease-causing organism
Ba body defence against disease
Ca drug used to treat disease
Da type of white blood cell
(b)
Which of the following is an example of indirect transmission of a pathogen?
[1 mark]
Ashaking hands with an infected person
Btouching a door handle previously touched by an infected person
Creceiving a blood transfusion contaminated with a pathogen
Dkissing an infected person
(c)
Explain two ways in which the human body defends itself against pathogens entering through the skin or the airways.
[2 marks]
Total for question 1: 4 marks
2
After the stomach bug outbreak in the boarding house, the school arranged a clean water supply directly to each dormitory, required staff to prepare food hygienically, and improved the sewage system connected to the building, in order to reduce the risk of further outbreaks.
(a)
Which measure most directly reduces the risk of a pathogen spreading via contaminated food?
[1 mark]
Aa clean water supply
Bsewage treatment
Chygienic food preparation
Dwaste disposal
(b)
Why is proper sewage treatment important in controlling the spread of disease?
[1 mark]
Ait kills pathogens already inside an infected person
Bit produces antibodies
Cit produces vaccines
Dit prevents pathogens in human waste contaminating water supplies and food
(c)
Explain why providing a clean water supply reduces the spread of transmissible diseases such as the stomach bug described.
[2 marks]
Total for question 2: 4 marks
3
A student who had never previously been exposed to a particular strain of flu virus caught the infection; several days later, blood tests showed that lymphocytes in their blood had begun producing antibodies specific to that flu virus, and the student made a full recovery.
(a)
Explain how antibodies help to destroy or remove a pathogen from the body, referring to antigens in your answer.
[3 marks]
(b)
Explain what is meant by active immunity, and explain why the student is now protected against this specific flu virus in the future.
[4 marks]
Total for question 3: 7 marks
4
A newborn baby receives some antibodies from their mother across the placenta and through breast milk, giving short-term protection against disease, before later being given a course of vaccinations at a clinic as part of a routine childhood immunisation programme.
(a)
Describe how vaccination works, and explain why it protects a person against a disease in the future in a similar way to catching the disease naturally.
[6 marks]
(b)
Explain why the passive immunity the baby receives from its mother is described as short-term, and explain why breast-feeding is important for a newborn baby's protection against disease, contrasting this with the active immunity the baby will later gain from vaccination.
[6 marks]
Total for question 4: 12 marks
5
In a crowded classroom, one student with a cold repeatedly coughed and sneezed without covering their mouth, releasing droplets containing the cold virus into the air; within a few days, several other students in the room had also developed cold symptoms.
(a)
How was the cold virus most likely transmitted between students in this scenario?
[1 mark]
Adirectly, through contaminated blood
Bindirectly, through the air
Cindirectly, through contaminated food
Ddirectly, through sexual contact
(b)
Which body defence most directly helps to prevent a pathogen breathed in through the nose from reaching the lungs?
[1 mark]
Amucus and hairs in the nose
Bstomach acid
Cskin
Dantibodies
(c)
Explain why a transmissible disease such as a cold can spread quickly between people in a crowded, enclosed room.
[2 marks]
Total for question 5: 4 marks
6
Before travelling abroad, a group of tourists were each given a vaccination against a disease common in the region they were visiting; the vaccine contained a weakened form of the pathogen that causes the disease.
(a)
What happens immediately after a vaccine containing a weakened pathogen is introduced into the body?
[1 mark]
Athe person immediately becomes immune without any immune response
Bthe weakened pathogen destroys the person's white blood cells
Cthe person develops the full disease
Dthe antigens on the weakened pathogen stimulate lymphocytes to produce antibodies specific to those antigens
(b)
Why does vaccination give long-term protection against a disease?
[1 mark]
Athe weakened pathogen remains permanently active in the blood
Bantibodies produced during vaccination never break down
Cmemory cells are produced, which allow a rapid antibody response if the real pathogen is met later
Dthe vaccine directly kills the pathogen if it is met again
(c)
Explain why vaccinating a large proportion of a population, rather than just a few individuals, is particularly effective at controlling the spread of a disease through that population.
[2 marks]
Total for question 6: 4 marks
7
A mother who had previously recovered from a bacterial infection had antibodies specific to that bacterium's antigens circulating in her blood; during pregnancy, some of these antibodies crossed the placenta into her developing baby, and after birth the baby continued to receive antibodies through breast milk.
(a)
Explain why the antibodies that protected the mother from the bacterial infection are able to protect her baby against the same bacterium.
[3 marks]
(b)
Explain why the protection the baby receives from its mother's antibodies is described as passive immunity, and explain why this protection will not last as long as if the baby had produced the antibodies itself.
[4 marks]
Total for question 7: 7 marks
8
During an outbreak of a bacterial disease in a community with an unsafe, contaminated water supply, public health workers both improved the water supply and sewage system, and ran a vaccination programme offering the population a vaccine containing a weakened form of the bacterium responsible.
(a)
Explain how each of the following would help to control the spread of this disease through the community: (i) providing a clean water supply and proper sewage treatment; and (ii) offering the population a vaccine against the bacterium.
[6 marks]
(b)
One resident of the community was breast-feeding a young baby throughout the outbreak. Explain what type of immunity the baby would gain from the mother's breast milk, and compare this with the type of immunity gained by adults in the community through vaccination, including why the vaccination programme would need to be repeated for new babies born after the outbreak, but not for adults who had already been vaccinated.
[6 marks]
Total for question 8: 12 marks

End of questions