Gastric (stomach) ulcer disease is most often caused by the bacterium Helicobacter pylori. Urease is an enzyme produced by H. pylori which catalyses the hydrolysis of urea into carbon dioxide and ammonia. The synthesised ammonia immediately reacts with water in the stomach to produce ammonium hydroxide in the immediate microenvironment of the bacterium. 

Part A

What would be the purpose of urease in terms of survival of H. pylori?     (3 marks)

Part B

Would you classify H. pylori is as an acidophile?  Briefly justify your response.    (3 marks)

Part C

Virulence mechanisms of pathogenic bacteria can be classed as having a role in (i) colonisation of the host (ii) pathogenesis or (iii) evasion of the host immune response.  Urease is a virulence factor for H. pylori, how would you classify it in terms of (i)-(iii) above, give a rationale for your answer.  (2 marks)