Organic Acid Fermentation Quiz

Getting ready for your exam? Let's break down the key concepts of organic acid fermentation, focusing on the star of the show: citric acid.

This guide is an interactive quiz. Answer each question, then click "Check Answer" to see the explanation and solidify your knowledge. Let's get started!

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Quiz Time: Acid Fundamentals

1. A molecule that can donate a proton (H⁺) is known as a...?

Lewis acid Brønsted-Lowry acid Polyprotic acid

2. If Acid A has a pK_a of 2.5 and Acid B has a pK_a of 4.5, which one is stronger?

Acid A Acid B They have the same strength

3. True or False: The pH measures the intrinsic strength of an acid compound, while the K_a measures the strength of a specific aqueous solution.

True False

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Quiz Time: Microbial Production

4. For anaerobic bacteria, the production of organic acids is primarily a way to...?

Create energy via oxidation Regenerate NADH Inhibit competing organisms

5. How do aerobic fungi, like Aspergillus niger, typically begin accumulating organic acids?

As a primary growth-dependent metabolite Only in the absence of oxygen Through an imbalance in essential nutrients

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Quiz Time: Citric Acid Properties & Uses

6. What is the proper chemical name for citric acid?

2-hydroxy-propane-1,2,3-tricarboxylic acid 1,2-dihydroxy-propane-tricarboxylic acid Acetic-hydroxy-malonic acid

7. Citric acid is a triprotic acid with pK_a values of 3.1, 4.7, and 6.4. What does "triprotic" mean?

It contains three carbon atoms. It can donate three protons. It is three times stronger than a monoprotic acid.

8. In the food industry, citric acid (E330) is NOT used for which of the following?

As an antioxidant to stabilize color and flavor. As a preservative to inactivate bacteria. As a natural sweetener. To provide a tart taste and reduce sweetness.

9. The ability of citric acid to bind metal ions is called chelation. This property is useful for...?

Preventing blood clotting by binding Ca²⁺. Acting as an antioxidant. Removing oxidation from metal surfaces. All of the above.

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Quiz Time: The History Buffs

10. True or False: Commercial citric acid production began in 1860 by fermenting sugar with fungi.

True False

11. Which microorganism was identified by James N. Currie in 1917 as the "ultimate producer" of citric acid for industrial fermentation?

Citromyces Aspergillus niger Saccharomyces cerevisiae