PORTAGE LEARNING EXAM zm zm
Exam Solution
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MCB 100 Exam 2 2026 A+ GRADE ASSURED COMPLETE
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SOLUTIONS AND VERIFIED ANSWERS (0E20D) zm zm zm zm
QUESTION 1 zm
Bacterial Growth zm
ANSWER
-Not about the growth of the individual -Growth of the bacterial population -
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when conditions are good for growth, the bacterial population increases at an exponential rate.
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QUESTION 2 zm
Bacteria
ANSWER
-reproduce by binary fission zm zm zm
QUESTION 3 zm
Generation Time zm
ANSWER
-time in which a microbial population doubles -Example: 30 minutes per generation
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QUESTION 4 zm
Growth Rate zm
ANSWER
-Generations per unit of time -[1 generation/(generation time)] -
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Example: 2 generations per hour If the population of bacteria in a culture doubles every 80 minutes,
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what is the growth rate? [60mins (1 hour) /80 minutes]= .75 gen/hour If the population of bacteri
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a in a culture doubles every 20 minutes, what is the growth rate? [60/20]=3 gen/hr
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, QUESTION 5 zm
MATHEMATICAL CONSIDERATIONS OF BACTERIAL GROWTH zm zm zm zm
ANSWER
-plotting on semi- zm zm
logarithmic graph paper allows you to draw a straight line for an exponential function.
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QUESTION 6 zm
If you inoculate a tube of broth with 350,000 bacterial cells and you incubate it until
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8 generations have passed, how many cells will be in the culture?
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ANSWER
Nf= (3.5*10^5)x(2^8) -
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After 8 generations (doublings), there will be about 8.96x10^7 cells in this culture.
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QUESTION 7 zm
The formula for determining the number of bacteria in a growing population
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ANSWER
Nf = Ni (2^n) Nf= the total # of bacteria Ni= initial # of bacteria n= # of generations
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QUESTION 8 zm
4 phases of a bacterial growth curve
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ANSWER
Phase 1: -Lag phase. -No detectable growth of the population of bacteria. Phase 2: -
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Log phase or Exponential phase. -
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The population of bacteria is growing at a steady, fast, exponential rate. Phase 3: -
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Stationary phase. - zm zm
The population stops growing because the medium has run out of some essential nutrient or is just
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too crowded. -zm zm
New cells are still forming, but the number of cells that form is equaled by the number of cells that
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mdie. Phase 4: -Decline or death phase. -
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The population of cells declines because toxic waste products have accumulated or essential nutrient
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s are used up. -May be difficult to detect by turbidity readings.
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QUESTION 9 zm
Methods of Enumerating Microorganisms zm zm zm
Exam Solution
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MCB 100 Exam 2 2026 A+ GRADE ASSURED COMPLETE
zm zm zm zm zm zm zm zm zm
SOLUTIONS AND VERIFIED ANSWERS (0E20D) zm zm zm zm
QUESTION 1 zm
Bacterial Growth zm
ANSWER
-Not about the growth of the individual -Growth of the bacterial population -
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when conditions are good for growth, the bacterial population increases at an exponential rate.
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QUESTION 2 zm
Bacteria
ANSWER
-reproduce by binary fission zm zm zm
QUESTION 3 zm
Generation Time zm
ANSWER
-time in which a microbial population doubles -Example: 30 minutes per generation
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QUESTION 4 zm
Growth Rate zm
ANSWER
-Generations per unit of time -[1 generation/(generation time)] -
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Example: 2 generations per hour If the population of bacteria in a culture doubles every 80 minutes,
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what is the growth rate? [60mins (1 hour) /80 minutes]= .75 gen/hour If the population of bacteri
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a in a culture doubles every 20 minutes, what is the growth rate? [60/20]=3 gen/hr
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, QUESTION 5 zm
MATHEMATICAL CONSIDERATIONS OF BACTERIAL GROWTH zm zm zm zm
ANSWER
-plotting on semi- zm zm
logarithmic graph paper allows you to draw a straight line for an exponential function.
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QUESTION 6 zm
If you inoculate a tube of broth with 350,000 bacterial cells and you incubate it until
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8 generations have passed, how many cells will be in the culture?
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ANSWER
Nf= (3.5*10^5)x(2^8) -
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After 8 generations (doublings), there will be about 8.96x10^7 cells in this culture.
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QUESTION 7 zm
The formula for determining the number of bacteria in a growing population
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ANSWER
Nf = Ni (2^n) Nf= the total # of bacteria Ni= initial # of bacteria n= # of generations
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QUESTION 8 zm
4 phases of a bacterial growth curve
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ANSWER
Phase 1: -Lag phase. -No detectable growth of the population of bacteria. Phase 2: -
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Log phase or Exponential phase. -
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The population of bacteria is growing at a steady, fast, exponential rate. Phase 3: -
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Stationary phase. - zm zm
The population stops growing because the medium has run out of some essential nutrient or is just
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too crowded. -zm zm
New cells are still forming, but the number of cells that form is equaled by the number of cells that
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mdie. Phase 4: -Decline or death phase. -
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The population of cells declines because toxic waste products have accumulated or essential nutrient
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s are used up. -May be difficult to detect by turbidity readings.
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QUESTION 9 zm
Methods of Enumerating Microorganisms zm zm zm
