Q: A researcher is measuring the biochemical oxygen demand (BOD) of a water sample. Which equation should be used to calculate BOD?

$\mathrm{BOD} = \mathrm{DO}_{\text{initial}} - \mathrm{DO}_{\text{final}}$

Question 1

Which of the following best describes the main difference between gram-positive and gram-negative bacterial cell walls?

Accepted Answer

Gram-positive bacteria have a thick peptidoglycan layer and lack an outer membrane, while gram-negative bacteria have a thin peptidoglycan layer and possess an outer membrane.

Question 2

A microbiologist is studying a microorganism that can survive in extremely high salt concentrations. Which term best describes this organism?

Accepted Answer

Halophile

Question 3

Which of the following is NOT a function of the bacterial cell membrane?

Accepted Answer

Protein synthesis

Question 4

During aerobic respiration, which equation correctly represents the overall redox reaction for glucose catabolism?

Accepted Answer

$\mathrm{C_6H_{12}O_6} + 6\mathrm{O_2} \rightarrow 6\mathrm{CO_2} + 6\mathrm{H_2O}$

Question 5

Which of the following statements about ATP is correct?

Accepted Answer

ATP stores energy in its high-energy phosphate bonds, which can be hydrolyzed to release energy for cellular processes.

Question 6

A chemolithoautotrophic organism uses reverse electron transport for CO$_2$ fixation. Why is this process necessary?

Accepted Answer

To produce NADPH required for biosynthetic reactions, since the electron donor is not sufficiently reducing.

Question 7

Which of the following best explains why mutations are important in microbial evolution?

Accepted Answer

Mutations increase genetic diversity, providing raw material for natural selection and adaptation to changing environments.

Question 8

Using the method of McCarty (1975), which equation would you use to represent the stoichiometry of a biological process involving substrate $S$ and product $P$?

Accepted Answer

$aS + bO_2 \rightarrow cP + dCO_2 + eH_2O$

Question 9

Which of the following is a major function of the bacterial cell wall?

Accepted Answer

Protection against osmotic lysis and maintenance of cell shape

Question 10

A researcher is measuring the biochemical oxygen demand (BOD) of a water sample. Which equation should be used to calculate BOD?

Accepted Answer

$\mathrm{BOD} = \mathrm{DO}_{	ext{initial}} - \mathrm{DO}_{	ext{final}}$

Question 11

Which of the following statements about the citric acid cycle is TRUE?

Accepted Answer

It provides both energy (ATP, NADH, FADH$_2$) and precursors for biosynthetic pathways.

Question 12

Which of the following is a correct description of chemotaxis in bacteria?

Accepted Answer

Movement toward or away from chemical stimuli using flagella.

Question 13

Which of the following is a correct stoichiometric equation for the formation of methane by methanogenic archaea?

Accepted Answer

$CO_2 + 4H_2 \rightarrow CH_4 + 2H_2O$

Question 14

Which of the following best describes the role of electron carriers in metabolism?

Accepted Answer

They transfer electrons between metabolic intermediates, facilitating energy production.

Question 15

A bacterium is exposed to harsh conditions and survives by forming an endospore. Which statement best explains this survival strategy?

Accepted Answer

Endospore formation allows the bacterium to remain dormant and resistant to heat, desiccation, and chemicals until conditions improve.

Question 16

Which of the following is a correct description of substrate-level phosphorylation?

Accepted Answer

ATP is generated directly from the transfer of a phosphate group from a high-energy substrate to ADP.

Question 17

Which of the following is a major difference between eukaryotic and prokaryotic cells?

Accepted Answer

Eukaryotic cells have membrane-bound organelles, while prokaryotic cells do not.

Question 18

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

Accepted Answer

Motility by rotation, allowing the cell to swim toward or away from stimuli

Question 19

Which of the following is a correct equation for the formation of TEAP (terminal electron accepting process) zone in an environment?

Accepted Answer

$SO_4^{2-} + 8H^+ + 8e^- \rightarrow S^{2-} + 4H_2O$

Microbiology Exam 1 Study Guide: Core Concepts and Processes

Study Guide - Practice Questions

Study Guide - Flashcards