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Biology LibreTexts

2.E: The Prokaryotic Cell: Bacteria (Exercises)

These are homework exercises to accompany Kaiser's "Microbiology" TextMap. Microbiology is the study of microorganisms, which are defined as any microscopic organism that comprises either a single cell (unicellular), cell clusters or no cell at all (acellular). This includes eukaryotes, such as fungi and protists, and prokaryotes. Viruses and prions, though not strictly classed as living organisms, are also studied.

Fundamental Statements for this Learning Object:

  1. Physical control includes such methods of control as high or low temperature, desiccation, osmotic pressure, radiation, and filtration.
  2. Chemical control refers to the use of disinfectants, antiseptics, antibiotics, and chemotherapeutic antimicrobial chemicals.
  3. Sterilization is the process of destroying all living organisms and viruses.
  4. Disinfection is the elimination of microorganisms, but not necessarily endospores, from inanimate objects or surfaces.
  5. Decontamination is the treatment of an object or inanimate surface to make it safe to handle.
  6. A disinfectant is an agents used to disinfect inanimate objects but generally to toxic to use on human tissues. 
  7. An antiseptic is an agent that kills or inhibits growth of microbes but is safe to use on human tissue.
  8. A sanitizer is an agent that reduces microbial numbers to a safe level.
  9. An antibiotic is a metabolic product produced by one microorganism that inhibits or kills other microorganisms.
  10. Synthetic chemicals that can be used therapeutically.
  11. An agent that is cidal in action kills microorganisms.
  12. An agent that is static in action inhibits the growth of microorganisms.
  13. Selective toxicity means that the chemical being used should inhibit or kill the intended pathogen without seriously harming the host. 
  14. A broad spectrum agent is one generally effective against a variety of Gram-positive and Gram-negative bacteria.
  15. A narrow spectrum agent generally works against just Gram-positives, Gram-negatives, or only a few bacteria.

2.1: Sizes, Shapes, and Arrangements of Bacteria

Study the material in this section and then write out the answers to these questions. Do not just click on the answers and write them out. This will not test your understanding of this tutorial.

  1. Match the following descriptions with the best answer.

    _____ Division in one plane; cocci arranged in pairs (ans)

    _____ Division in one plane; cocci arranged in chains (ans)

    _____ Division in two planes; cocci arranged in a square of four (ans)

    _____ Division in one plane; rods completely separate after division. (ans)

    _____ Division in one plane; rods arranged in chains. (ans)

    _____ A comma shaped bacterium. (ans)

    _____ A thin, flexible spiral. (ans)

    _____ A thick, rigid spiral. (ans)


    1. bacillus
    2. streptobacillus
    3. spirochete
    4. spirillum
    5. vibrio
    6. streptococcus
    7. staphylococcus
    8. diplococcus
    9. tetrad
    10. sarcina
  2. A Gram stain of discharge from an abcess shows cocci in irregular, grape-like clusters. What is the most likely genus of this bacterium? (ans)
  3. State the diameter of an average-sized coccus-shaped bacterium. (ans)
  4. Multiple Choice (ans)