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Question 19M.3.HL.TZ1.23b

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Date May 2019 Marks available [Maximum mark: 1] Reference code 19M.3.HL.TZ1.23b
Level HL Paper 3 Time zone TZ1
Command term Outline Question number b Adapted from N/A
b.
[Maximum mark: 1]
19M.3.HL.TZ1.23b

The diagram shows the bacterium Helicobacter pylori attacking the gastric mucosa of the stomach.

[Source: Reproduced from Gut, B A Hills, 34, 588–593, 1993 with permission from BMJ Publishing Group Ltd.]

 

(b)

The bacterium secretes an enzyme that breaks down urea, resulting in an increase in pH. Outline how this would help the bacterium survive in the stomach.

[1]

Markscheme

neutralizes the acid the stomach secretes that kills bacteria ✔

Examiners report

While most students achieved this mark, many seem to think that “higher pH values” indicate greater acidity.

Syllabus sections