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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
All textbooksBauman 6th EditionCh. 11 - Characterizing and Classifying ProkaryotesProblem 8
Chapter 11, Problem 8

Flexible spiral-shaped prokaryotes are __________ .


a. spirilla
b. spirochetes
c. vibrios
d. rickettsias

Verified step by step guidance
1
Step 1: Understand the morphology terms for prokaryotes. Prokaryotes can have different shapes such as cocci (spherical), bacilli (rod-shaped), spirilla (rigid spiral-shaped), spirochetes (flexible spiral-shaped), and vibrios (comma-shaped).
Step 2: Identify the key descriptor in the question: 'flexible spiral-shaped'. This means the prokaryote has a spiral shape but is not rigid, allowing it to bend or flex.
Step 3: Recall that 'spirilla' are spiral-shaped bacteria but are typically rigid and have external flagella.
Step 4: Recognize that 'spirochetes' are known for their flexible spiral shape and unique internal flagella called axial filaments, which allow them to move in a corkscrew motion.
Step 5: Conclude that the correct term for flexible spiral-shaped prokaryotes is 'spirochetes', which corresponds to option b.

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Key Concepts

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

Prokaryotic Cell Shapes

Prokaryotes exhibit various shapes including cocci (spherical), bacilli (rod-shaped), and spirilla (rigid spiral-shaped). Understanding these shapes helps in identifying and classifying bacteria based on their morphology.
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Spirochetes

Spirochetes are a group of flexible, spiral-shaped bacteria characterized by their unique axial filaments that enable corkscrew-like movement. This flexibility distinguishes them from rigid spirilla and is important in their identification.
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Distinction Between Spirilla and Spirochetes

While both spirilla and spirochetes are spiral-shaped, spirilla are rigid and move using external flagella, whereas spirochetes are flexible and move via internal axial filaments. This difference is key to correctly classifying spiral bacteria.
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Spiral-shaped Bacterial Cells
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