MicrobiologyLesson 1 of 1 in the course Microbial Metabolism

Microbial Fermentation: Pathways, Products, and Biochemical Identification

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

Fermentation allows cells to keep glycolysis running when they cannot carry out respiration. This lesson explains how fermentation restores an essential electron carrier, why it does not require oxygen, and how its ATP yield compares with respiration.

Cellular respiration depends on the organism's genes and on suitable environmental conditions. A cell may be unable to respire because it lacks an appropriate inorganic final electron acceptor, lacks genes for electron transport system components, or lacks genes for enzymes in the Krebs cycle.

All flashcards

What is fermentation?
A process that regenerates NAD+ by transferring electrons from NADH to an organic molecule, without an electron transport system.
What distinguishes homolactic fermentation?
Lactic acid is its only fermentation product.
What is substrate-level phosphorylation?
ATP production by direct transfer of a phosphate group to ADP.
How can lactic acid bacteria help inhibit pathogens?
They produce acid that maintains low-pH conditions, which can inhibit pathogen growth.
What are typical products of butyric acid fermentation?
Butyric acid, carbon dioxide, and hydrogen.

Quiz questions

  1. How does an API panel support microbial identification?Answer: A pattern of biochemical reactions is compared with reference profiles in a database.
  2. In yeast alcohol fermentation, what does alcohol dehydrogenase do?Answer: It transfers electrons from NADH to acetaldehyde, producing ethanol and NAD+.
  3. Which products can be formed in heterolactic fermentation?Answer: A mixture including lactic acid, ethanol or acetic acid, and carbon dioxide.
  4. What does an inverted Durham tube detect in a fermentation broth?Answer: Gas produced during microbial fermentation.
  5. Which fermentation pathway contributes to Swiss cheese flavor by producing propionic acid?Answer: Propionic acid fermentation.

Based on Microbiology by Nina Parker, Mark Schneegurt, Anh-Hue Thi Tu, Philip Lister, Brian M. Forster (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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