Question 1

Which scientist is credited with disproving the theory of spontaneous generation using swan-neck flasks, and what was a key outcome of his experiments?

Accepted Answer

Louis Pasteur; he demonstrated that microorganisms do not arise from nonliving matter when air is allowed but dust is excluded.

Question 2

Which of the following statements best describes the endosymbiotic theory?

Accepted Answer

Eukaryotic cells evolved when a larger cell engulfed smaller prokaryotes that survived and became mitochondria and chloroplasts.

Question 3

Which of the following is a unique feature of Gram-negative bacteria?

Accepted Answer

Lipopolysaccharide (LPS) in the outer membrane

Question 4

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

Accepted Answer

The cell will undergo plasmolysis as water leaves the cell.

Question 5

Which of the following best describes the function of bacterial fimbriae?

Accepted Answer

Attachment to surfaces and biofilm formation

Question 6

Which type of microscopy would be most appropriate for viewing the internal ultrastructure of a virus at nanometer resolution?

Accepted Answer

Transmission electron microscopy (TEM)

Question 7

During the Gram stain procedure, what color will a Gram-negative cell appear after the decolorization step?

Accepted Answer

Colorless

Question 8

Which of the following best describes a competitive inhibitor of an enzyme?

Accepted Answer

It binds to the active site, preventing substrate binding.

Question 9

Which of the following media types would you use to grow only Gram-negative bacteria while inhibiting Gram-positive bacteria?

Accepted Answer

Selective media

Question 10

Which group of organisms uses light as an energy source and carbon dioxide as a carbon source?

Accepted Answer

Photoautotrophs

Question 11

A bacterium that grows best at pH 3 and in hot springs at 70°C would be classified as:

Accepted Answer

Acidophile and thermophile

Question 12

Which of the following is true regarding the action of uncouplers in oxidative phosphorylation?

Accepted Answer

They allow electron transport and O$$_2$$ consumption to continue, but ATP synthesis decreases.

Question 13

Which of the following is a correct match between a biological macromolecule and its subunit?

Accepted Answer

Carbohydrate — Monosaccharide

Question 14

Which of the following best describes the function of NAD and FAD in cellular metabolism?

Accepted Answer

They are hydrogen and electron carriers involved in redox reactions.

Question 15

Which of the following statements about bacterial endospores is correct?

Accepted Answer

They are dormant, highly resistant structures formed to survive extreme conditions.

Question 16

Which of the following best describes the role of the Gas-Pak system in anaerobic culturing?

Accepted Answer

It releases carbon dioxide and hydrogen gas to remove oxygen from the environment.

Question 17

Which of the following is the correct sequence of the four phases of batch microbial growth?

Accepted Answer

Lag phase, log phase, stationary phase, death phase

Question 18

Which of the following is a property of a defined medium?

Accepted Answer

The exact chemical composition and concentrations of all components are known.

Question 19

Which of the following is a distinguishing feature of Mycoplasma species?

Accepted Answer

They lack a cell wall.

Question 20

Which of the following equations correctly represents the breakdown of hydrogen peroxide by catalase?

Accepted Answer

$$2 \mathrm{H}_2\mathrm{O}_2 \rightarrow 2 \mathrm{H}_2\mathrm{O} + \mathrm{O}_2$$

MMBIO 221 Exam 1 Review: Foundations of Microbiology

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