DP Chemistry (last assessment 2024)

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Question 19M.3.hl.TZ1.21b

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Date May 2019 Marks available [Maximum mark: 2] Reference code 19M.3.hl.TZ1.21b
Level hl Paper 3 Time zone TZ1
Command term Outline Question number b Adapted from N/A
b.
[Maximum mark: 2]
19M.3.hl.TZ1.21b

Mild heartburn is treated with antacids such as calcium carbonate.

(b)

Acid secretion can be regulated by other types of drugs such as omeprazole and ranitidine. Outline how each of these drugs acts to reduce excess stomach acid.

Omeprazole:

Ranitidine:

[2]

Markscheme

Omeprazole:
inhibits enzyme/«gastric» proton pump «which secretes H+ ions into gastric juice»
OR
 inhibits the H+/K+-ATPase system   [✔]


Ranitidine:
inhibits/blocks H2/histamine receptors «in cells of stomach lining»
OR
prevents histamine binding to H2/histamine receptors «and triggering acid secretion»  [✔]

 

Note: Accept “H2-receptor antagonist” for M2.

Examiners report

Many candidates correctly outlined how drugs such as omeprazole and ranitidine regulate acid secretion.

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