Question 1

A bacterial culture starts with 500 cells. If the generation time is 30 minutes, how many cells will there be after 3 hours, assuming exponential growth and no cell death? Use the formula $$N = N_0$ 	imes 2^n$$, where $$N is $$the final number of cells, $$N_0 is $$the initial number, and $$n is $$the number of generations.

Accepted Answer

32,000

Question 2

Which of the following correctly orders the listed microorganisms from smallest to largest in size?

Accepted Answer

Virus \u003c Bacterium \u003c Yeast \u003c Protozoan

Question 3

During cellular respiration, which macromolecule is LEAST likely to be used directly for ATP production under normal conditions?

Accepted Answer

Nucleic acids

Question 4

Which process is responsible for the majority of ATP production during aerobic respiration?

Accepted Answer

Electron transport chain

Question 5

A bacterium that grows best at pH 2 and can survive in highly acidic environments is classified as a:

Accepted Answer

Acidophile

Question 6

Which of the following best describes the difference between a capsule and a slime layer in bacteria?

Accepted Answer

A capsule is tightly bound and organized, while a slime layer is loosely attached and unorganized.

Question 7

Where does the electron transport chain occur in prokaryotes and eukaryotes, respectively?

Accepted Answer

Plasma membrane in prokaryotes; mitochondrial inner membrane in eukaryotes

Question 8

Which of the following is a distinguishing feature of Gram-negative bacterial cell walls compared to Gram-positive cell walls?

Accepted Answer

Presence of an outer membrane containing lipopolysaccharide (LPS)

Question 9

Which of the following best describes passive transport across a bacterial cell membrane?

Accepted Answer

Moves substances down their concentration gradient without energy input

Question 10

A relationship in which one organism benefits and the other is neither helped nor harmed is called:

Accepted Answer

Commensalism

Question 11

A microbiologist is trying to isolate a single bacterial species from a mixed sample. Which type of media should they use to inhibit the growth of unwanted bacteria while allowing the desired species to grow?

Accepted Answer

Selective media

Question 12

Which bacterial morphology is described as spherical cells arranged in clusters?

Accepted Answer

Staphylococci

Question 13

Endotoxins are:

Accepted Answer

Lipid A component of lipopolysaccharide in Gram-negative bacteria

Question 14

In a loosely sealed tube of nutrient broth, where would you expect to find growth of an obligate aerobe?

Accepted Answer

Only at the top of the tube

Question 15

Which scientist is credited with disproving spontaneous generation using a swan-neck flask experiment?

Accepted Answer

Louis Pasteur

Question 16

Which of the following best distinguishes a slime layer from a biofilm?

Accepted Answer

A slime layer is loosely attached to a single cell, while a biofilm is a community of microorganisms attached to a surface.

Question 17

In microbiology, 'growth' refers to:

Accepted Answer

Increase in the number of cells in a population

Question 18

A bacterial plasmid is best described as:

Accepted Answer

A small, circular piece of DNA that replicates independently of the chromosome

Question 19

Which of the following is an example of competitive inhibition of an enzyme?

Accepted Answer

A molecule binds to the active site, preventing substrate binding

Question 20

Which process involves the conversion of atmospheric $$\mathrm{N_2$}$$ into ammonia ($$\mathrm{NH_3$}) by $$certain bacteria?

Accepted Answer

Nitrogen fixation

Microbiology Exam 1 Study Guide: Key Concepts and Comparisons

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