Question 1

Growth is said to be __________ when all cellular components are synthesized at constant rates relative to one another.
ASM

Accepted Answer

The answer of Growth is said to be __________ when...

Question 2

Organisms that grow at 0$\degree$C and have a maximum growth temperature of 35$\degree$C are called

Accepted Answer

Organisms that grow at 0-20°C (32-68°F) and have a maximum growth temperature of 35°C (95°F) are called psychrotrophs. Psychrophiles are organisms that grow at temperatures below 0°C (32°F) and have a maximum growth temperature of around 20°C (68°F). Frigiphiles are organisms that grow at extremely cold temperatures, such as those found in the Arctic or Antarctic, and are not commonly studied. Mesophiles are organisms that grow at moderate temperatures, between 20-45°C (68-113°F).

Question 3

Organisms that ignore oxygen and grow equally well in its presence or absence are called

Accepted Answer

Organisms that grow equally well in the presence or absence of oxygen are called aerotolerant. They do not utilize oxygen for growth, but they are not harmed by it either. Facultative anaerobes can use oxygen if it is present but can also grow without oxygen. Microaerophiles require oxygen but only at low concentrations. Anoxygenic organisms do not use oxygen for growth and may even be inhibited by its presence.

Question 4

Microbial __________ is an increase in cell constituents that may or may not be accompanied by an increase in cell number.
Learning Outcome: 07.01.01 Describe binary fission as observed in bacteria and archaea
Section: 07.01

Accepted Answer

The answer of Microbial __________ is an increase in cell...

Question 5

Organisms that grow well at 0$\degree$C and have optimum growth temperatures of 15$\degree$C or lower are called

Accepted Answer

Organisms that grow well at cold temperatures and have an optimum growth temperature of 15°C or lower are called psychrophiles. Psychrotrophs can grow at cold temperatures but also have the ability to grow at higher (mesophilic) temperatures. Frigiphiles are a hypothetical class of extremophile bacteria that supposedly could thrive at temperatures near 0°F (-18°C). Mesophiles are organisms that grow best at moderate temperatures, typically between 20-45°C.

Question 6

Which of the following is considered a cardinal growth temperature?

Accepted Answer

All three temperatures, i.e., minimum, maximum, and optimum, are considered cardinal growth temperatures as they define the range of temperatures at which microorganisms can grow, and help in characterizing the growth response of microorganisms to temperature.

Question 7

In a continuous culture system,the rate at which media is added and removed is called the __________ rate.

Accepted Answer

The rate at which media is added and removed in a continuous culture system is called the dilution rate. This is because a certain volume of culture is removed and replaced with fresh media at a specific rate, which results in dilution of the culture. The other options, chemostatic, pass-through, and flow-through, do not accurately describe the process of adding and removing media in a continuous culture system.

Question 8

Which of these methods can be used to determine the number of viable microorganisms in a sample?

Accepted Answer

Measuring colony forming units per ml is the most accurate method for determining the number of viable microorganisms in a sample. This method involves diluting the sample and then plating it on a nutrient agar medium to allow visible colonies to form. Each visible colony represents one viable microorganism, and by counting the colonies, the number of viable microorganisms in the original sample can be calculated. The other methods listed may be useful for other types of measurements, but they are not reliable for determining the number of viable microorganisms in a sample.

Question 9

Organisms that do not require oxygen for growth but grow better in its presence are called

Accepted Answer

Facultative anaerobes are able to switch between aerobic and anaerobic metabolism depending on the presence of oxygen. They can grow in the absence of oxygen but grow better in its presence. Microaerophiles require low levels of oxygen for growth, while aerotolerant organisms can live in the presence of oxygen but don't use it for growth. Anoxygenic organisms do not produce oxygen as a byproduct of photosynthesis.

Question 10

A culture system with constant environmental conditions maintained through continual provision of nutrient and removal of wastes is called __________ culture system.

Accepted Answer

A continuous culture system provides a constant supply of nutrients and removal of wastes, allowing for sustained growth of microorganisms. In contrast, batch culture systems have a limited nutrient supply and accumulate waste products over time, leading to a decline in growth rate. Fed-batch culture systems involve intermittent addition of nutrients to prolong growth, and semicontinuous culture systems involve periodic removal of cells and addition of fresh medium.

Question 11

The __________ __________ is the length of time it takes for a population of microorganisms to double in number.

Accepted Answer

The answer of The __________ __________ is the length of...

Question 12

At 4:00 p.m.a closed flask of sterile broth is inoculated with 10,000 cells.The lag phase lasts 1 hour.At 9:00 p.m.the culture enters stationary phase with a population of 65 million cells.At what time is the population half maximal?

Accepted Answer

The population is half maximal when it reaches half of 65 million, which is 32.5 million. The exponential phase of growth occurs between the end of the lag phase (5:00 p.m.) and the beginning of the stationary phase (9:00 p.m.). Since the population increases exponentially during this time, to find when the population is half of its maximum (32.5 million), we look for the midpoint in time between the start and end of this phase. Given the exponential growth, the population would reach half its maximum size just before it stops growing. Since the stationary phase starts at 9:00 p.m., the population would be half maximal shortly before this, at 8:40 p.m.

Question 13

If all cell components are synthesized at constant rates relative to one another,the culture is said to be in __________ growth; however,if the rates of synthesis of some components change relative to the rates of synthesis of other components,the culture is said to be in __________ growth.

Accepted Answer

The answer of If all cell components are synthesized at...

Question 14

Which of the following can be used to estimate the number of microorganisms in a culture?

Accepted Answer

Direct counts of microbial cells can be used to estimate the number of microorganisms in a culture. Counts of viable cells using colony growth procedures can also be used to estimate the number of microorganisms in a culture. Measurements of microbial biomass can also be used to estimate the number of microorganisms in a culture. Therefore, all of the choices can be used to estimate the number of microorganisms in a culture.

Question 15

One of the major advantages of a continuous culture system is that the cells can be maintained in the exponential growth phase for extended periods of time.

Accepted Answer

Continuous culture systems allow for constant nutrient and waste removal, leading to a steady state of exponential growth. This allows for extended periods of time in which cells can be maintained in the exponential growth phase.

Question 16

An open system in which the growth rate is maintained by the removal and addition of media at such a rate as to maintain a constant cell density is called a

Accepted Answer

The answer of An open system in which the growth...

Question 17

At 4:00 p.m.a closed flask of sterile broth is inoculated with 10,000 cells.The lag phase lasts 1 hour.At 9:00 p.m.the log phase culture has population of 65 million cells.The approximate number of generations that has occurred is

Accepted Answer

The answer of At 4:00 p.m.a closed flask of sterile...

Question 18

At 4:00 p.m.a closed flask of sterile broth is inoculated with 10,000 cells.The lag phase lasts 1 hour.At 9:00 p.m.the log phase culture has a population of 65 million cells.The mean generation time is approximately

Accepted Answer

The answer of At 4:00 p.m.a closed flask of sterile...

Question 19

The growth rate of a given species of microorganism is dependent on the composition of the medium in which it is grown.

Accepted Answer

The growth rate of a microorganism is influenced by various factors, including the composition of the growth medium. Different microorganisms require different nutrients and conditions to grow and reproduce, and modifying the growth medium can affect their growth rate and metabolism. Therefore, the statement is true.

Question 20

An open system in which the growth rate is maintained by adding a nutrient (present in limiting quantities)at the same rate that medium containing microorganisms is removed is called

Accepted Answer

The description matches the characteristics of a chemostat, where a nutrient is continually added to the system to maintain a constant growth rate of microorganisms. A manostat is used for maintaining constant pressure, a turbidostat is used for controlling cell density, and a culturostat is not a commonly used term in microbiology.

Quiz 7: Microbial Growth

Growth is said to be __________ when all cellular components are synthesized at constant rates relative to one another. ASM

Organisms that grow at 0 $\degree$ C and have a maximum growth temperature of 35 $\degree$ C are called

Organisms that ignore oxygen and grow equally well in its presence or absence are called

Microbial __________ is an increase in cell constituents that may or may not be accompanied by an increase in cell number. Learning Outcome: 07.01.01 Describe binary fission as observed in bacteria and archaea Section: 07.01

Organisms that grow well at 0 $\degree$ C and have optimum growth temperatures of 15 $\degree$ C or lower are called

Which of the following is considered a cardinal growth temperature?

In a continuous culture system,the rate at which media is added and removed is called the __________ rate.

Which of these methods can be used to determine the number of viable microorganisms in a sample?

Organisms that do not require oxygen for growth but grow better in its presence are called

A culture system with constant environmental conditions maintained through continual provision of nutrient and removal of wastes is called __________ culture system.

The is the length of time it takes for a population of microorganisms to double in number.

At 4:00 p.m.a closed flask of sterile broth is inoculated with 10,000 cells.The lag phase lasts 1 hour.At 9:00 p.m.the culture enters stationary phase with a population of 65 million cells.At what time is the population half maximal?

If all cell components are synthesized at constant rates relative to one another,the culture is said to be in growth; however,if the rates of synthesis of some components change relative to the rates of synthesis of other components,the culture is said to be in growth.

Which of the following can be used to estimate the number of microorganisms in a culture?

One of the major advantages of a continuous culture system is that the cells can be maintained in the exponential growth phase for extended periods of time.

An open system in which the growth rate is maintained by the removal and addition of media at such a rate as to maintain a constant cell density is called a

At 4:00 p.m.a closed flask of sterile broth is inoculated with 10,000 cells.The lag phase lasts 1 hour.At 9:00 p.m.the log phase culture has population of 65 million cells.The approximate number of generations that has occurred is

At 4:00 p.m.a closed flask of sterile broth is inoculated with 10,000 cells.The lag phase lasts 1 hour.At 9:00 p.m.the log phase culture has a population of 65 million cells.The mean generation time is approximately

The growth rate of a given species of microorganism is dependent on the composition of the medium in which it is grown.

An open system in which the growth rate is maintained by adding a nutrient (present in limiting quantities) at the same rate that medium containing microorganisms is removed is called

Quiz 7: Microbial Growth

Growth is said to be __________ when all cellular components are synthesized at constant rates relative to one another. ASM

Organisms that grow at 0 °\degree° C and have a maximum growth temperature of 35 °\degree° C are called

Organisms that ignore oxygen and grow equally well in its presence or absence are called

Microbial __________ is an increase in cell constituents that may or may not be accompanied by an increase in cell number. Learning Outcome: 07.01.01 Describe binary fission as observed in bacteria and archaea Section: 07.01

Organisms that grow well at 0 °\degree° C and have optimum growth temperatures of 15 °\degree° C or lower are called

Which of the following is considered a cardinal growth temperature?

In a continuous culture system,the rate at which media is added and removed is called the __________ rate.

Which of these methods can be used to determine the number of viable microorganisms in a sample?

Organisms that do not require oxygen for growth but grow better in its presence are called

A culture system with constant environmental conditions maintained through continual provision of nutrient and removal of wastes is called __________ culture system.

The __________ __________ is the length of time it takes for a population of microorganisms to double in number.

At 4:00 p.m.a closed flask of sterile broth is inoculated with 10,000 cells.The lag phase lasts 1 hour.At 9:00 p.m.the culture enters stationary phase with a population of 65 million cells.At what time is the population half maximal?

If all cell components are synthesized at constant rates relative to one another,the culture is said to be in __________ growth; however,if the rates of synthesis of some components change relative to the rates of synthesis of other components,the culture is said to be in __________ growth.

Which of the following can be used to estimate the number of microorganisms in a culture?

One of the major advantages of a continuous culture system is that the cells can be maintained in the exponential growth phase for extended periods of time.

An open system in which the growth rate is maintained by the removal and addition of media at such a rate as to maintain a constant cell density is called a

At 4:00 p.m.a closed flask of sterile broth is inoculated with 10,000 cells.The lag phase lasts 1 hour.At 9:00 p.m.the log phase culture has population of 65 million cells.The approximate number of generations that has occurred is

At 4:00 p.m.a closed flask of sterile broth is inoculated with 10,000 cells.The lag phase lasts 1 hour.At 9:00 p.m.the log phase culture has a population of 65 million cells.The mean generation time is approximately

The growth rate of a given species of microorganism is dependent on the composition of the medium in which it is grown.

An open system in which the growth rate is maintained by adding a nutrient (present in limiting quantities) at the same rate that medium containing microorganisms is removed is called

Organisms that grow at 0 $\degree$ C and have a maximum growth temperature of 35 $\degree$ C are called

Organisms that grow well at 0 $\degree$ C and have optimum growth temperatures of 15 $\degree$ C or lower are called

The is the length of time it takes for a population of microorganisms to double in number.

If all cell components are synthesized at constant rates relative to one another,the culture is said to be in growth; however,if the rates of synthesis of some components change relative to the rates of synthesis of other components,the culture is said to be in growth.