Question 1

Which of the following elements is NOT considered a macronutrient required in relatively large amounts by microorganisms?

Accepted Answer

Copper (Cu)

Question 2

Proteins in microbial cells are primarily composed of which combination of elements?

Accepted Answer

C, H, O, N, S

Question 3

Which process describes the loss of electrons or an increase in oxidation state by a molecule, atom, or ion?

Accepted Answer

Oxidation

Question 4

A microorganism that uses organic molecules as both its carbon and energy source is classified as a:

Accepted Answer

Chemoorganoheterotroph

Question 5

Which of the following statements about micronutrients is TRUE?

Accepted Answer

They are often supplied in water or media components.

Question 6

Which nutritional type uses carbon dioxide as its sole or principal carbon source and obtains energy from the oxidation of inorganic compounds?

Accepted Answer

Chemolithoautotroph

Question 7

Which of the following is a correct description of facilitated diffusion in microbial cells?

Accepted Answer

It uses membrane-bound carrier molecules and moves substances down their concentration gradient.

Question 8

A bacterium is found to grow optimally at pH 9.5. How would you classify this organism?

Accepted Answer

Alkaliphile

Question 9

Which of the following transport mechanisms is unique to Bacteria and Archaea and involves chemical modification of the transported molecule?

Accepted Answer

Group translocation

Question 10

A microorganism that can grow in the presence or absence of oxygen, but grows better when oxygen is available, is classified as a:

Accepted Answer

Facultative anaerobe

Question 11

Which enzyme is responsible for catalyzing the conversion of superoxide radicals to oxygen and hydrogen peroxide in bacteria?

Accepted Answer

Superoxide dismutase (SOD)

Question 12

What is the main function of siderophores produced by microorganisms?

Accepted Answer

To aid in the uptake of ferric iron (Fe^{3+})

Question 13

Which of the following is a growth factor that must be supplied by the environment because the cell cannot synthesize it?

Accepted Answer

Amino acid

Question 14

Which of the following best describes the role of electrons in microbial metabolism?

Accepted Answer

Electrons play a role in energy production and reduction of $CO_2$ to form organic molecules.

Question 15

A microorganism isolated from deep-sea hydrothermal vents grows optimally at 100°C. Which category does it belong to?

Accepted Answer

Hyperthermophile

Question 16

Which of the following is TRUE regarding the adaptation of thermophiles to high temperatures?

Accepted Answer

Their membranes contain more saturated and branched lipids.

Question 17

Which of the following is a direct method for measuring microbial cell numbers?

Accepted Answer

Counting chambers

Question 18

Which process is defined as the destruction or removal of all viable organisms, including spores, from an object or environment?

Accepted Answer

Sterilization

Question 19

A bacterium that requires 2-10% oxygen for optimal growth is classified as a:

Accepted Answer

Microaerophile

Question 20

Which of the following statements about quorum sensing is CORRECT?

Accepted Answer

It involves the production of autoinducer molecules that regulate gene expression in response to cell density.

Microbial Nutrition and Environmental Factors Affecting Microbial Growth

Study Guide - Practice Questions