Ch. 11 - Characterizing and Classifying Prokaryotes

Bauman - Microbiology with Diseases by Taxonomy 6th Edition

Bauman6th EditionMicrobiology with Diseases by TaxonomyISBN: 9780134832302Not the one you use?Change textbook

Bauman 6th Edition

Ch. 11 - Characterizing and Classifying Prokaryotes

Problem 1

Chapter 11, Problem 1

Whereas the first edition of Bergey’s Manual relied on morphological and biochemical characteristics to classify microbes, the new edition focuses on ribosomal RNA sequences. List several other criteria for grouping and classifying bacteria.

Verified step by step guidance

Understand that bacterial classification can be based on multiple criteria beyond morphology, biochemical tests, and ribosomal RNA sequences.

Consider genetic methods such as DNA-DNA hybridization and whole-genome sequencing, which compare overall genetic similarity between bacterial strains.

Look at chemotaxonomic markers, including the composition of cell wall components (like peptidoglycan types), membrane lipids, and quinones, which can help differentiate bacterial groups.

Examine physiological and metabolic characteristics, such as oxygen requirements, temperature and pH tolerance, and specific metabolic capabilities (e.g., nitrogen fixation, fermentation pathways).

Include ecological and pathogenic traits, such as habitat preference, symbiotic relationships, and disease-causing potential, which provide additional context for classification.

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Key Concepts

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

Morphological and Biochemical Characteristics

These traditional criteria involve observing the shape, size, staining properties, and metabolic activities of bacteria. Morphology includes cell shape and arrangement, while biochemical tests assess enzyme activities and nutrient utilization, helping to differentiate species based on observable traits.

Ribosomal RNA (rRNA) Sequencing

rRNA sequencing analyzes the genetic sequences of ribosomal RNA genes, which are highly conserved among bacteria. This molecular method allows for precise phylogenetic classification by comparing evolutionary relationships, providing a more accurate and objective basis for grouping bacteria than morphology alone.

Additional Classification Criteria

Beyond morphology and rRNA, bacteria can be classified using criteria such as cell wall composition (Gram staining), lipid and fatty acid profiles, genomic DNA-DNA hybridization, metabolic capabilities, ecological roles, and pathogenicity. These diverse factors provide a comprehensive understanding of bacterial diversity and relationships.

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Related Practice

Textbook Question

The thick-walled reproductive spores produced in the middle of cyanobacterial filaments are called .

a. Akinetes

b. Terminal endospores

c. Metachromatic granules

d. Heterocysts

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Textbook Question

For each of the following statements that is true, write “true” in the blank. For each statement that is false, write the word(s) that should be substituted for the underlined word(s) to make the statement correct.

__________ All prokaryotes reproduce sexually.

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Textbook Question

Describe the location of these endospores within their cells.

(a) <Image>

(b) <Image>

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Textbook Question

The type of reproduction in prokaryotes that results in a palisade arrangement of cells is called ___________ .

a. pleomorphic division

b. endospore formation

c. snapping division