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Question 19M.3.HL.TZ1.24a

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Date May 2019 Marks available [Maximum mark: 2] Reference code 19M.3.HL.TZ1.24a
Level HL Paper 3 Time zone TZ1
Command term Identify Question number a Adapted from N/A
a.
[Maximum mark: 2]
19M.3.HL.TZ1.24a
(a)

The electron micrograph shows a section through an alveolus showing blood in a capillary.

[Source: © International Baccalaureate Organization 2019]

 

Identify the cells found at X and Y.

X: 

Y:

 

[2]

Markscheme

a. X: «type I» pneumocyte ✔ 

b. Y: endothelial cells ✔

Accept endothelium/capillary wall

Examiners report

Many students did correctly identify that X was a pneumocyte I, but very few correctly identified cell Y as an endothelial cell. Many assumed that the second cell would be a pneumocyte II.

Syllabus sections