A-LevelBiologyImmunity9700/21 · May/June 2021 · Q513 Marks

Much success was made in reducing the number of cases of malaria between 2000 and 2015.

(a)Explain how malaria is transmitted.[2]
(b)Diagnostic test strips for malaria contain monoclonal antibodies. The test strips detect antigens produced by the pathogens that cause malaria. Fig. 5.1 shows stages in the production of monoclonal antibodies. The information in three of these stages is incomplete. Complete Fig. 5.1. malarial antigen injected into mouse immune response occurs in mouse specific ........................................................................ divide to form many plasma cells plasma cells extracted from spleen of mouse plasma cells .............................................. with myeloma cells formation of ..................................................... cells myeloma cells [Figure 5.1][3]
(c)Fig. 5.2 shows two diagnostic test strips for malaria. [Figure 5.2]. A sample of blood from a person suspected of having malaria is put into the well labelled S. A buffer solution is put into the well labelled A. The buffer solution moves the blood towards the results window. A line at position C indicates that the test is working correctly. A line at position T indicates a positive result for malaria. State three advantages of using test strips for malaria, such as those shown in Fig. 5.2.[3]
(d)The highest number of cases of malaria occur in sub-Saharan Africa and South-East Asia. Discuss the factors that determine the global distribution of malaria.[5]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

Mark scheme

Marking points from the official mark scheme (May/June 2021). The mark or mark type is shown in brackets.

[2] 1 vector is female Anopheles (mosquito) ;
2 mosquito / (female) Anopheles, takes blood from infected person; I 'bites' alone
3 (vector/mosquito / Anopheles) inserts / AW, saliva / anticoagulant, with, pathogen / Plasmodium / parasite, into (blood of) uninfected person ;
R if incorrect type of pathogen
[3] B-lymphocytes / B-cells ;
fuse / combine / join / merge / AW ;
R hybridise / bind / bond
hybridoma;
[3] any three from
1 results are accurate (rely on monoclonal antibodies) ;
2 results are obtained quickly / diagnosis is quick ;
3 low cost/cheap ;
4 does not need highly trained medical professional / easy to read / easy to use / AW ;
5 does not need specialised equipment ;
6 easily, transported / distributed (in bulk) ;
7 can ensure appropriate treatment is given immediately malaria is confirmed ;
8 reduces unnecessary use of antimalarial drugs (just in case) ;
9 (a small area for S so) only a small sample of blood needed ;
10 AVP;
e.g. can identity different species of Plasmodium
I ref. to line C and working correctly
[5] ignore ref. to sickle cell anaemia
any five from
habitat of Anopheles mosquito
1 tropical / warm and humid / AW, climate / regions ;
A in context of global warming (increases life span of Anopheles)
2 in areas where, Anopheles (mosquito) / vector, occurs ;
3 Anopheles mosquitoes only live in humid conditions ;
4 warm temperatures for, development / growth, of, parasite / Plasmodium (in vector / mosquito) ;
5 warm temperature for, development / growth, of mosquito larvae ;
6 mosquitoes require bodies of, still / AW, water for breeding ;
A ponds, puddles, lakes, swamps
7 mosquitoes require places where there is sufficient rainfall ;
8 low altitude ;
resistance
9 insecticide / repellent, resistance of mosquitoes ;
10 drug resistance of parasite ;
prevention
11 in countries / areas, where, prevention / control measures, are not implemented by, governments / health authorities ;
12 further detail e.g. any example of a, prevention / control measure that is not used or not implemented fully ;
immunity
13 immunity to malaria in human population (limits distribution) ;
people
14 migration of infected people from areas (with high rates of malaria) ;
15 high rates of HIV infection ;