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Question 17N.2.SL.TZ0.01d

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Date November 2017 Marks available [Maximum mark: 2] Reference code 17N.2.SL.TZ0.01d
Level SL Paper 2 Time zone TZ0
Command term Evaluate Question number d Adapted from N/A
d.
[Maximum mark: 2]
17N.2.SL.TZ0.01d

The elasticity and resilience of the lungs are mainly provided by the protein elastin. Degradation of elastin produces peptides called desmosines.

Desmosines in urine or blood plasma have been proposed as biomarkers of lung degradation. The relationship between urine desmosines, plasma desmosines and COPD severity in patients was assessed.

[Source: Reproduced with permission of the © ERS 2012. European Respiratory Journal Apr 2012, 39 (4) 839–845; DOI: 10.1183/09031936.00064611]

(d)

Evaluate which of the two biomarkers would be the most useful indicator of COPD severity.

[2]

Markscheme

a. plasma desmosines

b. neither is very good due to large overlaps of ranges

    OWTTE

    OR

    the range of data for each category is less for plasma desmosines

    OR

    data are more reliable

c. the level of plasma desmosines increases with disease severity

d. easier/less invasive to take urine sample rather than a plasma sample

[Max 2 Marks]