Hi Shahd,

Yes, the most common way of overcoming competitive inhibition is by increasing the concentration of the substrate. However, based on the passage and question stem, it’s asking on how did H.pylori develop its resistance to urease inhibitors. Option A said increasing the substrate (i.e human host gastric cells), which technically the bacteria could not do since the concentration of substrates is controlled by its host. We could eliminate A then. Option B is a more reasonable answer, as H.pylori does produce urease and could basically produce urease in excess until all the urease inhibitors are eliminated from the stomach. By then, H.pylori could go back and attack its host’s stomach.

Hope these help!

Hi Shahd,

Good question! In agreement with Youssef's comment below, the typical way to overcome competitive inhibition is to add more substrate (in this case - human gastric cells) to out-compete the inhibitor (urease inhibitors). But as mentioned, in this passage the amount of substrate must be held constant as we cannot reasonably increase the amount of human stomach cells.

As such, if we increase the amount of enzyme present (urease), we create more open active sites relative to the amount of inhibitor. This will effectively increase and restore Vmax, allowing more substrate to be converted to product.

Hope this helps!
- Sydney