Question 1

Which of the following best describes an essential nutrient for microorganisms?

Accepted Answer

A nutrient that is required for life and survival and must be specifically provided to the cell because the cell cannot manufacture it on its own.

Question 2

Which of the following is an example of a macronutrient required by microorganisms?

Accepted Answer

Magnesium ($$Mg^{2+})$$

Question 3

A bacterium that uses sunlight as its energy source and $$CO_2 as $$its carbon source is classified as a:

Accepted Answer

Photoautotroph

Question 4

Which process describes the movement of water across a selectively permeable membrane from an area of low solute concentration to an area of high solute concentration?

Accepted Answer

Osmosis

Question 5

A bacterial cell is placed in a hypertonic solution. What is the most likely outcome?

Accepted Answer

The cell will lose water and shrink (plasmolysis).

Question 6

Which of the following statements about passive transport is TRUE?

Accepted Answer

It relies on the random movement of molecules and does not require energy input.

Question 7

Facilitated diffusion differs from simple diffusion in that facilitated diffusion:

Accepted Answer

Requires specific carrier or channel proteins to transport substances across the membrane.

Question 8

Which of the following is NOT a feature of active transport in microbial cells?

Accepted Answer

The movement of substances only down their concentration gradient.

Question 9

A microbe that can survive at cold temperatures but grows best at temperatures below $$15^{\circ}C$ is classified as a:

Accepted Answer

Psychrophile

Question 10

Which of the following best explains why macroscopic life depends on chemical cycling performed by microbes?

Accepted Answer

Microbes recycle essential elements, making chemical building blocks available for plants and animals.

Question 11

Which of the following is an example of a heterotroph?

Accepted Answer

A bacterium that uses organic molecules as both its energy and carbon source.

Question 12

A bacterium is placed in distilled water (0% NaCl). What type of solution is this relative to the cell, and what is the likely effect?

Accepted Answer

Hypotonic; water will enter the cell, possibly causing it to swell and burst.

Question 13

Which of the following best describes the role of nitrogen-fixing bacteria in the environment?

Accepted Answer

They convert atmospheric $$N_2$$ into biologically usable forms such as $$NH_4$$^+$$.

Question 14

Which of the following is a correct example of group translocation in bacteria?

Accepted Answer

The uptake of glucose that is chemically modified as it enters the cell.

Question 15

A microbe that grows optimally at $$37^{\circ}C$ and cannot survive at 55$$^{\circ}$$C is $$most likely a:

Accepted Answer

Mesophile

Question 16

Which of the following statements about facilitated diffusion is FALSE?

Accepted Answer

It requires direct input of ATP.

Question 17

Which of the following is a likely consequence if a cell is placed in an isotonic solution?

Accepted Answer

There will be no net movement of water, and the cell will remain the same size.

Question 18

Which of the following best describes the process of bulk transport (endocytosis and exocytosis) in eukaryotic microbes?

Accepted Answer

It involves the movement of large particles, cells, or liquids into or out of the cell via vesicle formation.

Question 19

Which of the following is a reason why thermophilic bacteria can survive at higher temperatures than mesophilic bacteria?

Accepted Answer

Their proteins and membranes are more heat-stable and resistant to denaturation.

Microbial Growth: Nutrition, Ecology, and Laboratory Cultivation

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