Helicobacter pylori uses the enzyme urease to counteract a chemical defense in the human organ in which it lives. This chemical defense is
a. lysozyme.
b. hydrochloric acid.
c. superoxide radicals.
d. sebum.
e. complement.

Verified step by step guidance

Step 1: Understand the habitat of Helicobacter pylori, which is the human stomach, an environment known for its highly acidic conditions.

Step 2: Recognize that Helicobacter pylori produces the enzyme urease, which catalyzes the hydrolysis of urea into ammonia and carbon dioxide.

Step 3: Connect the production of ammonia by urease to its role in neutralizing the acidic environment, thereby protecting the bacteria from stomach acid.

Step 4: Identify the chemical defense in the stomach that urease helps to counteract, which is the acidic pH primarily due to hydrochloric acid.

Step 5: Review the answer choices and select the one that corresponds to the stomach's chemical defense neutralized by urease, which is hydrochloric acid.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Helicobacter pylori and its survival mechanism

Helicobacter pylori is a bacterium that colonizes the human stomach, an acidic environment hostile to most microbes. It produces the enzyme urease, which breaks down urea into ammonia and carbon dioxide, helping neutralize stomach acid and protect the bacterium from acidic damage.

Role of urease enzyme

Urease catalyzes the hydrolysis of urea into ammonia and carbon dioxide. The ammonia raises the local pH around H. pylori, neutralizing the stomach's hydrochloric acid and allowing the bacterium to survive and colonize the gastric mucosa.

Chemical defenses of the stomach

The stomach defends against pathogens primarily through hydrochloric acid, which creates a highly acidic environment (pH ~1-2) that kills many microbes. Other defenses include enzymes and immune factors, but hydrochloric acid is the main chemical barrier targeted by H. pylori.

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