A-LevelBiologyInfectious diseases9700/21 · Oct/Nov 2018 · Q112 Marks

Fig. 1.1 shows the human gas exchange system. [Figure 1.1]

(a)Name the structures labelled A, B, and C in Fig. 1.1. A B C[3]
(b)Name a non-infectious disease that affects the human gas exchange system.[1]
(c)Malaria is an infectious disease. Name the pathogen that causes malaria.[1]
(d)There are a number of vaccines being developed to help control the spread of malaria. Explain why vaccination programmes have not been able to eradicate malaria.[3]
(e)Fig. 1.2 shows the distribution of malaria in the Americas in 2012. Key area P = countries where malaria is always present area Q = countries where malaria is not present Fig. 1.2 Suggest the factors, other than lack of vaccines, that could be restricting the distribution of malaria to area P.[4]

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 (Oct/Nov 2018). The mark or mark type is shown in brackets.

[3] (a) A trachea; A windpipe I ref. to cartilage rings
[3] (a) B bronchiole ; I respiratory / terminal, before bronchiole
[3] (a) C alveoli; A alveolus / air sac / alveolar sac
[1] (b) any one from lung cancer; emphysema; chronic bronchitis ; COPD; cystic fibrosis ; AVP; e.g. asthma must be non-infectious
[1] (c) Plasmodium, falciparum / vivax / ovale / malariae ;
[3] (d) any three from pathogen (because) four / several, different, causative species / AW, (with different antigens);
[3] (d) (pathogen has) many antigens as it is eukaryotic / many genes coding for antigens;
[3] (d) ref. to mutation changing antigens;
[3] (d) pathogen has different stages of life cycle (within human) with different antigens ; I ref. to antigenic shift
[3] (d) antigenic concealment / pathogen spends part of life cycle within host cells / AW ;
[3] (d) vaccine A short time in blood plasma ref. to more than one type of vaccine needed ;
[3] (d) suggestion that antigens used have not given the strongest immune response ;
[3] (d) vaccination programme ref. to only trial programmes ; A programmes not global
[3] (d) ref. to not achieving herd immunity / not enough people (successfully) vaccinated ;
[3] (d) detail; e.g. lack of willingness to be vaccinated lack of trained people to give vaccines poor nutrition and poor immune response
[4] (e) any four from (max 1 for list of factors without explanation) assume in context of comparison with area Q
[4] (e) ref. to a suitable climate for Anopheles, e.g. tropical / subtropical / hot and humid ;
[4] (e) presence of Anopheles species which carry Plasmodium ;
[4] (e) ref. Anopheles breeding sites present / (many) water sources (suitable for breeding) ;
[4] (e) difficulty in controlling / lack of control, of Anopheles breeding sites ; AW, e.g. stagnant water not drained
[4] (e) lack of / cannot afford, spraying with, insecticide / pesticide / repellents;
[4] (e) insecticide-resistant forms of Anopheles exist;
[4] (e) lack of /insufficient use of, mosquito nets;
[4] (e) mosquito nets not impregnated with insecticide ;
[4] (e) lack of, artemisinin drugs / drugs to treat disease ;
[4] (e) drug-resistant forms of Plasmodium exist;
[4] (e) idea of Plasmodium requiring temperatures of approximately 20°C (in vector); A area P has temperature / conditions for survival of Plasmodium
[4] (e) ref. to difficulties in diagnosing disease (so delay / no treatment); e.g. lack of diagnostic tests lack of trained personnel
[4] (e) AVP ;; e.g. some countries in area Q have Anopheles but control is good,
[4] (e) ref. to feature of Anopheles species present in area P
[4] (e) feed at all times during the day
[4] (e) feed only on humans
[4] (e) good host for reproduction of Plasmodium
[4] (e) poor education so people don't know how to protect themselves from malaria