A-LevelBiologyInfectious diseases9700/23 · May/June 2023 · Q211 Marks

The number of cases of tuberculosis (TB) is affected by many biological, social and economic factors.

(a)(i)The number of reported cases of TB in the USA between 1980 and 2000 is shown in Fig. 2.1. Describe the trends shown in Fig. 2.1 between 1980 and 2000.[3]
(a)(ii)The number of reported cases of TB between 1984 and 1992 in the USA may have been affected by an increase in the number of people infected with HIV. Explain how an increase in the number of people infected with HIV could have affected the number of TB cases.[2]
(b)Mycobacterium tuberculosis is a species of bacterium that causes TB. Strains of M. tuberculosis have evolved resistance to some of the antibiotics used to treat the disease. State two ways that the impact of antibiotic resistance can be reduced.[2]
(c)(i)TB can affect every part of the human gas exchange system, including the trachea, bronchi and alveoli. The cartilage in the bronchi can be damaged in some people with TB. Suggest the effect that damage to cartilage may have on the bronchi.[1]
(c)(ii)Table 2.1 shows four types of cell and three structures found in the gas exchange system. Complete Table 2.1 to show the distribution of cell types in each structure of the gas exchange system. Use a tick (✔) if the cell type is present in the structure and a cross (X) if the cell type is not present. Put a tick (✔) or a cross (X) in every box. Table 2.1 cell type alveolus bronchus trachea ciliated epithelial cell goblet cell smooth muscle cell squamous epithelial cell [3]

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 2023). The mark or mark type is shown in brackets.

[3] max two if, number of (reported) cases/AW, not stated any three from: 1 overall decrease in number of reported cases from 1980 to 2000 / over the time period / AW ; 2 from, 27 600/ 27 700 / 27 800, to, 16 300/ 16 400, cases ; A manipulated data e.g. decline of, 11200 / 11300 / 11 400/11 500 cases 3, 4 additional trends ;; e.g. decrease from 1980 to 1984 increase between 1988 and 1992 or (overall) increase between 1984 to 1992 decrease after 1992 (to 2000) little change / slight increase and decrease / AW, between 1984 and 1988 5 use of comparative values from Fig. 2.1 to support mps, 3/4;
[2] HIV-infected people may develop a weak(ened) immune system or people with, HIV/AIDS have a weak(ened) immune system ; A poor immune response A idea of more susceptible to disease caused by, Mycobacterium, tuberculosis/bovis A TB is an opportunistic disease (of people with HIV/AIDS) increased risk of latent TB becoming active in (many) people, living with HIV / with HIV/AIDS ; AW detail of weak immune system ; e.g. decrease in number of,T-lymphocytes / T helper cells poor, humoral / B-lymphocyte, response AVP; idea of more cases of TB owing to more people infected with HIV increases risk of spreading to uninfected people
[2] any two from: 1 prescribe / take, antibiotics, only when (absolutely) necessary ; A examples e.g. do not use for viral infections do not use as preventative medicine 2 make sure, correct / effective, antibiotic(s), prescribed / used AW A ref. to, broad spectrum / narrow spectrum, antibiotics, qualified or make sure people take the correct dose or complete course / follow instructions for use, of antibiotics A ref. to DOTS ; 3 develop new, antibiotics / antibacterials; 4 use other antibacterials; if mp3 and 4 not gained, allow one mark for vary antibiotic treatment or use a number of different antibiotics at the same time 5 (named) measures to, prevent infection / break transmission cycle (to reduce the need for antibiotic use); e.g. vaccines good hygiene in hospitals quarantine people who have multi-drug resistant bacterial infections 6 report, cases / patterns, of antibiotic resistance; 7 reduce/control, antibiotics in, agriculture / animals used for food; 8 ref. to education for, healthcare professionals / public, to reduce impact of antibiotic resistance ; 9 AVP; e.g. ref. to monitoring situation to check if antibiotic is effective WHO Global Plan to End TB
[1] (bronchi) may, collapse / lose (structural) support;
[3] one mark each correct column = 3 marks ;;; if 0 or 1 mark gained, check for correct row to max 2 In the whole table: • if only ticks are used, assume blanks are crosses • if only crosses are used, assume blanks are ticks If there are ticks and crosses and blanks in the whole table, R the columns or rows with the blank(s) cell type alveolus bronchus trachea ciliated epithelial cell X ✓ ✓ goblet cell X ✓ ✓ smooth muscle cell X ✓ ✓ squamous epithelial cell ✓ X X