Question 1

Which of the following elements is NOT considered an essential macronutrient for microbial growth?

Accepted Answer

Zinc

Question 2

A microorganism that uses inorganic CO$$_2 as $$its carbon source and derives energy from sunlight is classified as:

Accepted Answer

Photoautotroph

Question 3

Which of the following best describes a saprobe?

Accepted Answer

A microorganism that feeds on organic detritus from dead organisms

Question 4

In a hypertonic environment, what happens to a bacterial cell without a cell wall?

Accepted Answer

It shrinks and becomes dehydrated due to water loss

Question 5

Which transport mechanism requires energy expenditure and specific membrane proteins to move molecules against a concentration gradient?

Accepted Answer

Active transport

Question 6

A microbe that grows optimally at temperatures above 45°C and is commonly found in volcanic soil is called a:

Accepted Answer

Thermophile

Question 7

Which of the following statements about obligate anaerobes is TRUE?

Accepted Answer

They die in the presence of oxygen

Question 8

The pH scale ranges from 0 to 14. Which of the following organisms would most likely thrive at pH 1?

Accepted Answer

Obligate acidophile

Question 9

Halobacterium and Halococcus are examples of microbes that:

Accepted Answer

Require high concentrations of salt to survive

Question 10

Which of the following is a mutualistic relationship?

Accepted Answer

Both organisms benefit and the relationship is obligatory

Question 11

Biofilms are difficult to eradicate because:

Accepted Answer

They involve synergistic partnerships among multiple microbial inhabitants

Question 12

During binary fission, the parent cell duplicates its chromosome and divides into two daughter cells. The time required for this process is called:

Accepted Answer

Generation time

Question 13

If a bacterial population doubles every 30 minutes, how many cells will there be after 2 hours, starting from a single cell? Use the formula $$N = N_0$ 	imes 2^n$$, where $$N_0 is $$the initial number of cells and $$n is $$the number of generations.

Accepted Answer

32

Question 14

Which phase of the bacterial growth curve is characterized by equal rates of cell birth and cell death?

Accepted Answer

Stationary phase

Question 15

A flow cytometer is advantageous over direct microscopic cell counting because it can:

Accepted Answer

Measure cell size and differentiate between live and dead cells

Question 16

Which of the following is NOT a function of micronutrients in microbial cells?

Accepted Answer

Cell structure and metabolism

Question 17

A chemoheterotroph obtains its energy and carbon from:

Accepted Answer

Organic compounds

Question 18

Which environmental factor is most likely to affect the function of metabolic enzymes in microbes?

Accepted Answer

Temperature

Question 19

Which of the following methods allows scientists to quantify bacteria in environmental samples without culturing them?

Accepted Answer

Real-time PCR

Question 20

A microorganism that can survive short exposure to high temperatures but is normally a mesophile is called:

Accepted Answer

Thermoduric

Microbial Nutrition and Environmental Factors Affecting Microbial Growth

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