Outline the function of the stomach in food digestion.

State a mechanism by which the stomach destroys pathogens.

There are times when pathogenic bacteria infect the stomach, causing ulcers.

State a pathogenic bacterium that can cause stomach ulcers.

There are times when pathogenic bacteria infect the stomach, causing ulcers.

Explain how proton pump inhibitors (PPIs) reduce conditions that favour ulcer formation.

a. produces acid to break down molecules;

b. churns food for mechanical digestion;

c. produces proteases to digest proteins/peptides;

Allow pepsin.

Do not allow “acid kills bacteria”.

production of hydrochloric acid/HCl

Helicobacter pylori/H. pylori

a. acidity is achieved by a proton pump/H⁺, K⁺-ATPase;

b. exchange of H⁺ from the cytoplasm for K⁺ ions in the lumen;

c. PPIs bind irreversibly to the (proton) pump;

d. lowering amount of acid produced/H⁺;

Most candidates could outline at least one function of the stomach, and the strongest candidates provided complete answers.

This was done poorly, as most provided vague answers.

The majority of candidates could state Helicobacter pylori, some with minor distortion, but answers with other names were seen, including Escherichia coli and Vibrio cholerae.

Strong candidates distinguished themselves in this question, although most could state that their action lowered the volume of hydrochloric acid produced.