5 marksYoung mammals that are orphaned can be bottle-fed.
Fig. 1 shows a newborn tiger cub sucking on a bottle.
Fig. 1
Sucking is an example of an involuntary action observed in newborn mammals.
State the name given to involuntary actions.
[1]
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3 marksVaccines provide protection against certain diseases.
State the type of immunity gained by being vaccinated against a disease.
[1]
Describe the advantage of the type of immunity identified at part (i).
[2]
2 marksVaccines may contain one of several different substances that helps with developing immunity against disease.
Give two examples of these substances that could be found in a vaccine.
2 marksThe MMR vaccine is administered to children by the age of five and provides protection against mumps, measles and rubella.
In the year 2020 there were 693 928 children in England that celebrated their fifth birthday.
654 197 of these children had received their first MMR dose.
Calculate the percentage of five-year-old children that had received their first MMR vaccine.
2 marksIn order to prevent the outbreak of epidemics or pandemics in a population it is very important that a large percentage of the population is vaccinated.
Explain the importance of this.
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Fig. 1 shows a sample of human blood as seen under a microscope.
In Fig. 1 one cell is labelled X. Cells of this type produce antibodies.
Fig. 1
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2 marksWhite blood cells form part of the immune system in the human body which protects against infection by pathogens.
Outline the possible responses of these white blood cells to an infection by pathogens.
4 marksBeing vaccinated is another way to gain protection against infection by pathogens.
Describe how vaccines protect against infection by pathogens.
2 marksThe measles vaccine will not give a child immunity against the influenza virus.
Explain the reason for this.
2 marksThe 'flu (influenza) is an example of a disease against which we typically don't build immunity; this is the main reason why we need to get vaccinated against flu regularly.
Explain why it is difficult to develop immunity against certain pathogens, such as the influenza virus.
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2 marksBreastfeeding is an example of passive immunity which provides the baby with short-term protection against pathogens.
Explain why passive immunity only provides short-term protection against pathogens.
1 markNot all babies are breastfed.
Suggest one way in which these babies may gain immunity against pathogens.
3 marksAn American TV crew visited a remote tribe in the Brazilian rainforest to make a documentary.
Two weeks after the crew's visit, six members of the tribe died of influenza and many more were seriously ill.
The members of the TV crew did not show symptoms of influenza during their visit, but members of the remote tribe died from the disease.
Suggest an explanation for this.
2 marksThe Center for Disease Control and Prevention estimated that 3.55 × 107 individuals were infected with influenza in the United States during the 2018-19 'flu season.
Of those individuals affected, an estimated 3.42 × 104 died, sadly.
Based on these estimated figures, calculate the percentage of people infected with influenza that died from the disease during the 2018-19 'flu season.
Show your work and give your answer to two decimal places.
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2 marksCGRP is a protein found in the human brain. High levels of CGRP has been linked to the occurrence of migraines in sufferers. A possible treatment under investigation involves injecting mice with human CGRP.
Explain how the immune system of mice would respond to the CGRP injection.
2 marksCGRP binds to receptors in the brain that triggers blood vessels to dilate. The dilation of blood vessels is responsible for the intense pain associated with migraines.
The substances produced by the immune system of mice, after the CGRP injection, are extracted and modified before being sold as medication. When administered to migraine sufferers, these substances will bind to CGRP proteins in the brain.
Suggest how this may act as a treatment for migraines.
2 marksComplete the graph in Fig. 1 to show how the number of antibodies changes when a vaccinated person becomes infected with a live pathogen.
3 marksAfter many people were vaccinated against Covid-19, a new variant of the virus emerged that had different shaped antigens to the first version of the virus.
This caused the vaccine to be less effective against the virus.
Explain why having different shaped antigens caused the vaccine to be less effective against the virus.
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