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Ch. 10 - Controlling Microbial Growth in the Body: Antimicrobial Drugs
Bauman - Microbiology with Diseases by Taxonomy 6th Edition
Bauman6th EditionMicrobiology with Diseases by TaxonomyISBN: 9780134832302Not the one you use?Change textbook
All textbooksBauman 6th EditionCh. 10 - Controlling Microbial Growth in the Body: Antimicrobial DrugsProblem 10
Chapter 10, Problem 10

PABA is __________ .
a. A substrate used in the production of penicillin
b. A type of β-lactamase
c. Molecularly similar to cephalosporins
d. Used to synthesize folic acid

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1
Understand what PABA stands for: Para-aminobenzoic acid, a compound involved in bacterial metabolism.
Recall the role of PABA in microbiology: it is a precursor molecule used by bacteria to synthesize folic acid, which is essential for their growth and DNA synthesis.
Analyze each option in the context of PABA's function:
- Option a: PABA is not a substrate for penicillin production; penicillin is produced by fungi, not bacteria, and PABA is unrelated to this process.
- Option b: PABA is not a type of β-lactamase; β-lactamases are enzymes that break down β-lactam antibiotics.
- Option c: PABA is not molecularly similar to cephalosporins; cephalosporins are β-lactam antibiotics with a distinct structure.
- Option d: PABA is used by bacteria to synthesize folic acid, making this the correct description.

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Key Concepts

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

PABA (Para-aminobenzoic acid)

PABA is an organic compound that serves as a precursor in the bacterial synthesis of folic acid. It is essential for bacteria because folic acid is required for DNA and RNA synthesis, making PABA critical for bacterial growth and replication.
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Folic Acid Synthesis in Bacteria

Bacteria synthesize folic acid from PABA, which is not obtained from the environment. This pathway is a target for antibiotics like sulfonamides, which inhibit enzymes involved in folic acid production, thereby blocking bacterial growth.
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Role of PABA in Antibiotic Mechanisms

PABA is structurally similar to sulfonamide antibiotics, which act as competitive inhibitors of PABA in folic acid synthesis. Understanding this similarity explains how sulfonamides disrupt bacterial metabolism without affecting human cells.
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Related Practice
Textbook Question

Which of the following statements is false concerning antiviral drugs?

a. Macrolide drugs block attachment sites on the host cell wall and prevent viruses from entering.

b. Drugs that neutralize the acidity of phagolysosomes prevent viral uncoating.

c. Nucleotide analogs can be used to stop microbial replication.

d. Drugs containing protease inhibitors retard viral growth by blocking the production of essential viral proteins.

Textbook Question

A man has been given a broad-spectrum antibiotic for his stomach ulcer. What unintended consequences could arise from this therapy?

Textbook Question

Compare and contrast the actions of polyenes, azoles, allylamines, and polymyxin.

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Textbook Question

What is the difference in drug action of synergists contrasted with that of antagonists?