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Biology LibreTexts

17.E: Bacterial Growth and Energy Production (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.

17.1: Bacterial Growth

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

  1. Match the following:

    _____ A population doubles every generation time. (ans)

    _____ One cell splits in two. (ans)

    _____ The time it takes for a population of organisms to double in number. (ans)

    1. binary fission
    2. generation time
    3. geometric progression
  2. If you started with 1000 E. coli with a generation time of 30 minutes, how many bacteria would you have after 3 hours? (ans)
  3. Match the following:

    _____ Phase where the population grows slowly or stops growing because of decreasing food, increasing waste, and lack of space. The rate of replication is balanced out by the rate of inhibition or death. (ans)

    _____ Phase where the population dies exponentially from the accumulation of waste products, although the rate of death depends on the degree of toxicity and the resistance of the species. (ans)

    _____ Phase where growth is relatively flat and the population appears either not to be growing or growing quite slowly. During this phase the newly inoculated cells are adapting to their new environment and synthesizing the molecules they will need in order to grow rapidly. (ans)

    _____ Phase where the population increases geometrically as long as there is sufficient food and space for growth. (ans)

    1. Lag phase
    2. Exponential (log) growth phase
    3. Stationary phase
    4. Death (decline) phase

17.2: Factors that Influence Bacterial Growth

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

  1. Matching

    _____ Bacteria that grow best at moderate temperatures. Their optimum growth temperature is between 25C and 45C. (ans)

    _____ Cold-loving bacteria. Their optimum growth temperature is between -5C and 15C. They are usually found in the Arctic and Antarctic regions and in streams fed by glaciers. (ans)

    _____ Organisms that grow with or without oxygen, but generally better with oxygen. (ans)

    _____ Organisms that grow onlyin the absense of oxygen and, in fact, are often inhibited or killed by its presense. (ans)

    _____ An environment where the water concentration is greater outside the cell and the solute concentration is higher inside. Water goes into the cell. (ans)

    _____ Organisms that use the oxidation and reduction of chemical compounds as their primary energy source. (ans)

    _____ Organisms that use light as an energy source and carbon dioxideas their main carbon source. (ans)

    _____ Organisms that use organic compounds as both an energy source and a carbon source. (ans)

    _____ Organisms that use lightas an energy source but cannot convert carbon dioxide into energy. Instead they use organic compounds as a carbon source. (ans)

    1. photoautotrophs
    2. photoheterotrophs
    3. chemolithoautotrophs
    4. chemooganoheterotrophs
    5. phototroph
    6. heterotroph
    7. hypertonic
    8. hypotonic
    9. obligate aerobe
    10. facultative anaerobe
    11. obligate anaerobe
    12. psychrophile
    13. mesophile
    14. thermophile

17.4: Cellular Respiration

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

  1. An exergonic processes by which energy released by the breakdown of organic compounds such as glucose can be used to synthesize ATP, the form of energy required to do cellular work. This best describes:
    1. anabolism (ans)
    2. catabolism (ans)
  2. Intermediate molecules that link catabolic and anabolic pathways; can be either oxidized to generate ATP or can be used to synthesize macromolecular subunits such as amino acids, lipids, and nucleotides. (ans)
  3. Define cellular respiration. (ans)
  4. Pathways that do not require oxygen are said to be:
    1. aerobic (ans)
    2. anaerobic (ans)
  5. Name an exergonic pathway that requires molecular oxygen (O2). (ans)
  6. Name two anaerobic exergonic forms of cellular respiration. (ans)