Question 1

Which of the following statements best explains why bacterial electron transport chains (ETCs) are more diverse than mitochondrial ETCs?

Accepted Answer

Bacterial ETCs can use a variety of terminal electron acceptors and donors, allowing adaptation to different environments.

Question 2

In the electron transport chain, electrons pass through a series of redox reactions, releasing energy in small steps. This energy is primarily used to:

Accepted Answer

Pump protons across a membrane to generate a proton motive force ($$\Delta p).$$

Question 3

Which equation correctly represents the relationship between the proton motive force ($$\Delta p$$), membrane potential ($$\Delta \Psi$$), and pH gradient ($$\Delta pH$$)?

Accepted Answer

$$\Delta p = \Delta \Psi + 2.3 \dfrac{RT}{F} \Delta pH$$

Question 4

Which of the following is NOT a possible terminal electron acceptor for bacterial respiration?

Accepted Answer

Glucose (C$$_6H$_{12}O$_6)$$

Question 5

A pure sulfur bacterium cannot generate enough energy to reduce NADP$$^+$$ directly. What alternative strategy does it use to produce NADPH?

Accepted Answer

It uses reverse electron flow, consuming ATP to push electrons from the PMF to NADP$$^+.$$

Question 6

Which of the following best describes cyclic photophosphorylation in photosynthetic bacteria?

Accepted Answer

It is anoxygenic, involves only one photosystem, and produces ATP but not NADPH.

Question 7

During mitochondrial electron transport, which complex is responsible for pumping the most protons into the intermembrane space?

Accepted Answer

Complex I

Question 8

Which process allows bacteria to survive in low oxygen environments by using alternative electron acceptors?

Accepted Answer

Anaerobic respiration

Question 9

Which of the following bacteria is known for its social motility and ability to form fruiting bodies?

Accepted Answer

Myxobacteria

Question 10

Which nitrogen transformation is performed by nitrifying bacteria?

Accepted Answer

Conversion of ammonia (NH$$_3) to $$nitrite (NO$$_2^-)$$

Question 11

Which bacterial structure is most directly responsible for the selective permeability that impacts chemical disinfection?

Accepted Answer

Cytoplasmic membrane

Question 12

Which of the following methods is most effective for sterilizing heat-sensitive medical instruments?

Accepted Answer

Filtration through a 0.2 $$\mum $$filter

Question 13

Which of the following is a common misconception about the use of heat for virus inactivation?

Accepted Answer

Heat is more effective against enveloped viruses due to their sensitivity to environmental changes.

Question 14

Which of the following is NOT a way that excited electrons lose energy?

Accepted Answer

Direct conversion to ATP

Question 15

Which of the following bacteria can fix nitrogen and plant cells but is most effective for legume roots due to the microaerobic, symbiotic relationship?

Accepted Answer

Rhizobium

Question 16

Which of the following is a correct statement about sulfate-reducing bacteria?

Accepted Answer

They produce hydrogen sulfide (H$$_2S) as a $$metabolic product.

Question 17

Which of the following is a critical consideration when using alcohol to disinfect medical instruments?

Accepted Answer

Alcohol is ineffective on intact biofilms and tissues.

Question 18

Which of the following is NOT a method to pasteurize liquids?

Accepted Answer

Filtration through a 0.2 $$\mum $$filter

Question 19

Which of the following is a unique characteristic of Caulobacter?

Accepted Answer

It can replicate its stalked cell via asymmetric cell division.

Microbial Electron Transport, Metabolism, and Environmental Adaptations: Study Notes

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