Question 1

An organism that can grow at 0°C but whose optimum temperature is 20- 40°C is considered ___________. These organisms are ___________(more/less) widely distributed in nature than organisms that grow exclusively at cold temperatures.

Accepted Answer

The answer of An organism that can grow at 0°C...

Question 2

The optimal growth pH represents the pH of the intracellular environment.

Accepted Answer

The optimal growth pH represents the pH of the extracellular environment, i.e. the pH of the surrounding medium in which the microorganism is growing. The intracellular pH may differ from the optimal growth pH due to various factors such as metabolic processes, ion exchange, and transport mechanisms.

Question 3

For most purposes, viable counting usually gives accurate information about the number of active cells present in a culture volume.

Accepted Answer

Viable counting involves determining the number of cells that are able to grow and divide, which provides an accurate estimate of the number of active cells present in a culture volume. However, it is important to note that viable counting methods can be affected by factors such as clumping of cells or the presence of dead cells, which can lead to under- or over-estimation of the actual cell count.

Question 4

With a few minor exceptions, the time required for a bacterial growth cycle is generally the same, regardless of the bacterial species.

Accepted Answer

The time required for a bacterial growth cycle varies depending on the bacterial species and environmental conditions. Some bacteria can complete a growth cycle in just a few hours, while others may take several days.

Question 5

Many obligate anaerobes are killed by oxygen.

Accepted Answer

Obligate anaerobes are organisms that cannot survive in the presence of oxygen. Oxygen can be toxic to them and can either kill them or inhibit their growth.

Question 6

The main reactions of cell synthesis are the polymerization reactions that make macromolecules from monomers.

Accepted Answer

Polymerization reactions are indeed the main reactions of cell synthesis, as they are responsible for building macromolecules such as proteins, nucleic acids, and carbohydrates from their respective monomers.

Question 7

Taq polymerase was isolated from a thermophile and is used in the polymerase chain reaction (PCR) technique.

Accepted Answer

Taq polymerase was originally isolated from the bacterium Thermus aquaticus, which is a thermophilic microorganism found in hot springs. Taq polymerase is used in the PCR technique because it can withstand the high temperatures used in the denaturation step of the reaction.

Question 8

An alkaliphile would likely be found in soda lakes and high carbonate soils.

Accepted Answer

Alkaliphiles are microorganisms that thrive in alkaline environments, typically with a pH of 9 or higher. Soda lakes and high carbonate soils are examples of such environments, making it likely to find alkaliphiles there.

Question 9

During stationary phase, many cellular functions continue, including___________ and some___________.

Accepted Answer

The answer of During stationary phase, many cellular functions continue,...

Question 10

An increase in microbial density is synonymous with growth.

Accepted Answer

Microbial growth is defined as an increase in the number of microbial cells or microbial biomass. Therefore, an increase in microbial density, which refers to the number of microbes per unit of volume, is synonymous with growth.

Question 11

Turbidity measurements are rapid but are not particularly accurate.

Accepted Answer

The answer of Turbidity measurements are rapid but are not...

Question 12

Substances added to a culture to keep the pH constant are known as ____________ .

Accepted Answer

The answer of Substances added to a culture to keep...

Question 13

The rates of exponential growth (in the exponential phase) vary greatly.

Accepted Answer

Exponential growth rates can be influenced by a variety of factors such as nutrient availability, temperature, population density, and competition. Therefore, different organisms or populations can have very different exponential growth rates.

Question 14

The process by which macromolecules are synthesized from monomers is called___________ .

Accepted Answer

The answer of The process by which macromolecules are synthesized...

Question 15

FtsZ is related to ___________, the important cell division protein in eukaryotes.

Accepted Answer

The answer of FtsZ is related to ___________, the important...

Question 16

Organisms with a specific requirement for salt are known as___________ .

Accepted Answer

The answer of Organisms with a specific requirement for salt...

Question 17

___________is the term used to describe the maintaining of cultures in a constant environment. The system is then said to be in a(n)___________ .

Accepted Answer

The answer of ___________is the term used to describe the...

Question 18

Probably the most important environmental factor affecting microbial growth is ____________.

Accepted Answer

The answer of Probably the most important environmental factor affecting...

Question 19

Cold environments are usually sterile.

Accepted Answer

Cold environments can still harbor microorganisms and organic matter, albeit at a slower rate than warmer environments. Therefore, they are not necessarily sterile.

Question 20

The most common type of continuous culture device is called a(n)___________ .

Accepted Answer

The answer of The most common type of continuous culture...

Quiz 5: Microbial Growth

An organism that can grow at 0°C but whose optimum temperature is 20- 40°C is considered _. These organisms are _(more/less) widely distributed in nature than organisms that grow exclusively at cold temperatures.