Bacterial Cell Growth Requirements Quiz

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What is the term used to describe the time between bacterial cell divisions?

Division period

Generation time (correct)

Fission duration

Replication interval

Which of the following is NOT a physical factor that influences the rate of bacterial growth?

Carbon availability (correct)

Temperature

pH

Osmotic pressure

What is the optimum temperature range for the growth of psychrotrophs?

20°C to 30°C (correct)

50°C to 60°C

0°C or below

15°C or below

Which group of bacteria is most likely to cause disease or food spoilage in cold environments?

Psychrotrophs Signup and view all the answers

Which of the following statements about mesophiles is correct?

All of the above. Signup and view all the answers

What is the minimum temperature at which thermophiles can grow?

45°C Signup and view all the answers

What is the primary role of water in the environment for microorganisms?

All of the above Signup and view all the answers

What is the optimal water activity (aw) required for microbial growth and multiplication?

0.95 Signup and view all the answers

How do freeze-dried foods prevent spoilage by microorganisms?

By decreasing the water activity Signup and view all the answers

What is the primary function of a solidifying agent in a culture medium?

To create a solid substrate for microbial growth Signup and view all the answers

What is the unique property of agar that allows it to be used as a solidifying agent in culture media?

It melts above 95°C and does not solidify until it reaches 40°C Signup and view all the answers

How does the water activity of foods relate to the rate of food spoilage?

Foods with high water activity spoil more rapidly Signup and view all the answers

Which of the following statements about thermophiles is correct?

They are a type of archaebacteria that thrive in volcanic and ocean vents. Signup and view all the answers

Which of the following statements about pH preferences of microorganisms is correct?

Neutrophiles, including most human pathogens, grow optimally at a pH range of 5.4 to 8.5. Signup and view all the answers

What is the primary reason for using buffers in microbial growth media?

To stabilize the pH of the media and prevent fluctuations. Signup and view all the answers

Which of the following statements about osmotic pressure and microbial growth is correct?

Hypertonic solutions remove water from cells, causing plasmolysis. Signup and view all the answers

Which of the following microorganisms is classified as an acidophile?

Lactobacillus Signup and view all the answers

Which of the following pH ranges is associated with alkaliphiles?

7.0 to 12.0 or higher Signup and view all the answers

What is the main characteristic of polysaccharides made by red algae?

They cannot be degraded by most bacteria Signup and view all the answers

What is the purpose of chemically defined media?

To provide a source of carbon and energy for chemoheterotrophs Signup and view all the answers

Which statement about anaerobic growth media is true?

They contain ingredients that chemically combine with oxygen Signup and view all the answers

What is the main advantage of complex media over chemically defined media?

Complex media are widely used for heterotrophic bacteria and fungi Signup and view all the answers

Which method is used to directly measure bacterial growth?

Viable membrane count Signup and view all the answers

If a dilution of 1/10,000 contains 40 CFU (Colony Forming Units), what does N0 represent?

The initial number of bacteria in the sample Signup and view all the answers

Which of the following elements is NOT required as an enzyme cofactor for bacteria?

Chlorine Signup and view all the answers

What type of bacteria is Pseudomonas, a common nosocomial pathogen?

Obligate Aerobe Signup and view all the answers

Which of the following is a characteristic of Facultative Anaerobes?

They can use oxygen, but can also grow in its absence. Signup and view all the answers

Which trace element is commonly found in tap water and used as an enzyme cofactor?

Molybdenum Signup and view all the answers

Which type of bacteria can carry out fermentation regardless of the presence of oxygen?

Aerotolerant Anaerobes Signup and view all the answers

Which element is used to form proteins and some vitamins in bacteria?

Sulfur Signup and view all the answers