Biology - Chapter 6: Microbial Growth

Which of the following is the best definition of generation time? a. The minimum rate of doubling. b. The time needed for nuclear division. c. The length of time needed for lag phase. d. The length of time needed for a cell to divide. e. The duration of log phase.

Which of the following represent a truest statement about the resulting prokaryotic daughter cells? a. They are unable to divide. b. They are genetically identical to the parent. c. Four new daughter cells result from one parental cell. d. It occurs following mitosis of the chromosome. e. They share characteristics of both parental cells.

Which of the following growth type:temperature pairs is mismatched? a. Psychrotroph - growth at 0°C b. Hyperthermophiles - growth at 100°C c. Thermophile - growth at 37°C d. Psychrophile - growth at 15°C e. Mesophile - growth at 25°C

Which of the following characteristics is a hallmark of bacterial growth? a. Since the number of bacterial cells double after each round of replication, the number of cells exponentially increases. b. After several rounds of division, the genetic diversity of the bacterial population will be extreme. c. All daughter cells produced will be smaller than the parent. d. Doubling times vary with each generation. e. Bacterial growth is fast because all bacterial cells undergo mitosis.

Most bacteria grow best at pH: a. 5 b. 14 c. 9 d. 7 e. 1

If you begin with three cells, how many cells would you have after three rounds of division? a. 6 b. 9 c. 24 d. 18 e. 12

The addition of which of the following to a culture medium will stabilize an acidic environment? a. Heat b. Sugars c. Buffers d. strong base e. pH

In Figure 6.1, which line shows the growth of an obligate aerobe incubated anaerobically? a. Can't tell with information provided. b. a c. c d. b

An ____ is killed by atmospheric oxygen. a. Microaerophile b. Obligate aerobe c. Aerotolerant anaerobe d. Aerobe e. Obligate anaerobe

In Figure 6.1, which line best depicts the human pathogen Chlamydia trachomatis growing inside the human body? a. can't tell b. b c. c d. a

In Figure 6.2, which section shows a growth phase where the number of cells dying equals the number of cells dividing? a. b b. c c. a d. d e. a and c

Salts and sugars work to preserve foods by creating (a): a. Hypertonic environment. b. Depletion of nutrients. c. Lower osmotic pressure. d. Altered pH. e. Osmotic lysis.

In Figure 6.1, which line best illustrates a mesophile at 5°C above its optimum temperature? a. Can't tell with information provided. b. c c. a d. b

A culture medium that allows the identification of colonies of a desired organism is a ___ medium. a. Selective b. Chemically defined c. Complex d. Differential e. Reducing

In Figure 6.1, which line best depicts a facultative anaerobe in the absence of O2? a. a b. Can't tell with information provided. c. c d. b

An organism that grows using anaerobic metabolism exclusively, but continues to grow the despite of oxygen is called a/an ________. a. Facultative anaerobe b. Aerotolerant anaerobe c. Anaerobe d. Microaerophile e. Aerobe

In Figure 6.2, which sections of the graph illustrate a logarithmic change in cell numbers? a. c and d b. b only c. a and b d. b and d e. a and c

In Figure 6.1, which line best depicts an obligate anaerobe in the presence of O2 ? a. b b. Can't tell with information provided. c. a d. c

An exposure to ________ protects against infection with smallpox. a. antibody b. normal microbiota c. cowpox lesions d. smallpox bacterial fragments e. varicella

Why do cells that are placed in fresh media experience a delay before entering logarithmic phase of growth? a. Some cells are dying and must be eliminated prior to cell division b. Cells are preparing to enter a dormant state for long-term survival. c. The cells need to switch their metabolic state from a dormant one to an actively growing one. d. The number of cells that are made is equal to the number of cells that are dying, resulting in no net growth.

In Figure 6.1, which line best depicts a psychrotroph incubated at 0°C? a. c b. b c. Can't tell with information provided. d. a

Which group of microorganisms is most likely to spoil a freshwater trout preserved with salt? a. Psychrophiles b. Anaerobes c. Hyperthermophiles d. Facultative halophiles e. Thermophiles

In Figure 6.1, which line best depicts a psychrophile incubated at room temperature? a. Can't tell with information provided. b. c c. a d. b

The term aerotolerant anaerobe refers to an organism that: a. Is killed by oxygen. b. Uses oxygen or grows without oxygen. c. Doesn't use oxygen, but tolerates it. d. Prefers to grow without oxygen. e. Requires less oxygen than is present in air.

Bacteria require nitrogen for the synthesis of ________. a. sugars b. proteins. c. lipids d. carbohydrates. e. fatty acids

Stationary phase can best be defined as: a. The length of time it takes for lag phase. b. The minimum rate of doubling. c. an equilibrium between cell death and growth. d. The length of time it takes for a cell to divide. e. The duration of log phase.