Skip to ContentGo to accessibility page
OpenStax Logo
Microbiology

Fill in the Blank

MicrobiologyFill in the Blank

Fill in the Blank

17.

When prokaryotes live as interacting communities in which one population benefits to the harm of the other, the type of symbiosis is called ________.

18.

The domain ________ does not include prokaryotes.

19.

Pathogenic bacteria that are part of the transient microbiota can sometimes be eliminated by ________ therapy.

20.

Nitrogen-fixing bacteria provide other organisms with usable nitrogen in the form of ________.

21.

Rickettsias are ________ intracellular bacteria.

22.

The species ________, which belongs to Epsilonproteobacteria, causes peptic ulcers of the stomach and duodenum.

23.

The genus Salmonella belongs to the class ________ and includes pathogens that cause salmonellosis and typhoid fever.

24.

The bacterium that causes syphilis is called ________.

25.

Bacteria in the genus Rhodospirillum that use hydrogen for oxidation and fix nitrogen are ________ bacteria.

26.

Streptococcus is the ________ of bacteria that is responsible for many human diseases.

27.

One species of Streptococcus, S. pyogenes, is a classified as a ________ pathogen due to the characteristic production of pus in infections it causes.

28.

Cutibacterium belongs to ________ G+C gram-positive bacteria. One of its species is used in the food industry and another causes acne.

29.

The length of the branches of the evolutionary tree characterizes the evolutionary ________ between organisms.

30.

The deeply branching bacteria are thought to be the form of life closest to the last universal ________ ________.

31.

Many of the deeply branching bacteria are aquatic and hyperthermophilic, found near underwater volcanoes and thermal ocean ________.

32.

The deeply branching bacterium Deinococcus radiodurans is able to survive exposure to high doses of ________.

33.

________ is a genus of Archaea. Its optimal environmental temperature ranges from 70 °C to 80 °C, and its optimal pH is 2–3. It oxidizes sulfur and produces sulfuric acid.

34.

________ was once thought to be the cause of periodontal disease, but, more recently, the causal relationship between this archaean and the disease was not confirmed.

PreviousNext
Order a print copy
Citation/Attribution
Reuse and redistribution of this content in digital or print format:
  • This book may not be used in the training of large language models or otherwise be ingested into large language models or generative AI offerings without OpenStax's prior written permission.
  • This book uses the Creative Commons Attribution-NonCommercial-ShareAlike License, which means that you can reuse and modify the material only for noncommercial purposes, must attribute OpenStax, and must distribute any derivative works under the same license.
  • Any commercial printing of this textbook, including using a local or custom printer, must be approved by OpenStax, and proper citation provided.
  • OpenStax-copyrighted images, activities, assessments, and similar components of this book are subject to the same licensing – CC-BY-NC-SA. They can be used for noncommercial purposes with attribution. Commercial use requires permission.
  • Permission requests: Anyone who intends to incorporate this content (including text, images, and other components) into large language models, use it in AI offerings, use it commercially (including in print), and/or has questions about another use case is welcome to complete our reuse request form.
Attribution information
  • If you are redistributing all or part of this book in a noncommercial print format, then you must include on every physical page the following attribution:

    Access for free at https://openstax.org/books/microbiology/pages/1-introduction

  • If you are redistributing all or part of this book in a noncommercial digital format, then for every page that includes OpenStax content, you must license the derivative work under the same CC-BY-NC-SA license as the original, and include on every digital page view the following attribution:

    Access for free at https://openstax.org/books/microbiology/pages/1-introduction

Citation information

The information below includes the information needed to generate citations in most major styles (APA, MLA, etc.); you must reformat and organize the information as needed to fit the requirements of the style. Use the information below to generate a citation. We recommend using a citation tool such as this one.

© Jul 8, 2026 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike License. The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo, and Rice University name, and Rice University logo trademarks, or wordmarks are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.