Q: Which equation correctly represents the overall reaction for the oxidation of glucose during aerobic respiration?

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

Question 1

Which of the following statements best explains why aerobic respiration yields more ATP than fermentation?

Accepted Answer

Aerobic respiration uses oxygen as the terminal electron acceptor, allowing complete oxidation of substrates and continuous reoxidation of NADH.

Question 2

During the conversion of pyruvate to acetyl CoA, which of the following occurs?

Accepted Answer

Pyruvate undergoes oxidative decarboxylation, releasing CO$$_2$$ and reducing NAD$$^+ to $$NADH.

Question 3

Which of the following best describes the role of the mitochondrial cristae?

Accepted Answer

Cristae increase the surface area of the inner membrane, providing more space for electron transport and ATP synthesis.

Question 4

A muscle cell is exposed to dinitrophenol (DNP), an uncoupling agent. What is the most likely outcome?

Accepted Answer

Electron transport and O$$_2$$ consumption continue, but ATP synthesis is abolished due to loss of the proton gradient.

Question 5

Which equation correctly represents the overall reaction for the oxidation of glucose during aerobic respiration?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} + 6\,\mathrm{O_2$} ightarrow 6\,\mathrm{CO_2$} + 6\,\mathrm{H_2O} + 	ext{energy}$$

Question 6

Which of the following is a direct product of the citric acid cycle per turn, excluding the conversion of pyruvate to acetyl CoA?

Accepted Answer

2 CO$$_2$$, 1 ATP (or GTP), 3 NADH, and 1 FADH$$_2$$

Question 7

Which respiratory complex is responsible for transferring electrons from NADH to coenzyme Q and pumps 4 protons across the inner mitochondrial membrane per electron pair?

Accepted Answer

Complex I (NADH–coenzyme Q oxidation complex)

Question 8

A patient is exposed to cyanide, which binds to the Fe-Cu center of cytochrome c oxidase. What is the most immediate cellular consequence?

Accepted Answer

Electron transport is halted, preventing ATP synthesis and leading to cell death.

Question 9

Which of the following best describes the chemiosmotic model proposed by Peter Mitchell?

Accepted Answer

ATP synthesis is driven by the electrochemical proton gradient established by proton pumping during electron transport.

Question 10

How many ATP molecules are estimated to be generated per NADH and per FADH$$_2$$ during oxidative phosphorylation?

Accepted Answer

3 ATP per NADH and 2 ATP per FADH$$_2$$

Question 11

Which of the following statements about β oxidation of fatty acids is correct?

Accepted Answer

Each cycle of β oxidation produces one FADH$$_2$$, one NADH, and one acetyl CoA.

Question 12

Which of the following is a key regulatory mechanism for the pyruvate dehydrogenase (PDH) complex?

Accepted Answer

PDH is inhibited by ATP, NADH, and acetyl CoA, and activated by AMP, NAD$$^+$$, and free CoA.

Question 13

Which of the following best explains why the maximum theoretical yield of ATP per glucose is rarely achieved in cells?

Accepted Answer

The proton gradient is used for other processes besides ATP synthesis, reducing the actual ATP yield.

Question 14

Which of the following is NOT a function of the citric acid cycle?

Accepted Answer

Directly synthesizing glucose from CO$$_2$$ and water.

Question 15

Which of the following best describes the role of coenzyme Q (ubiquinone) in the electron transport chain?

Accepted Answer

Coenzyme Q collects electrons from various dehydrogenases and transfers them between respiratory complexes, accepting and releasing both protons and electrons.

Question 16

A cell is found to have a high [ATP]/[ADP] ratio. What effect will this have on the activity of the pyruvate dehydrogenase (PDH) complex?

Accepted Answer

PDH will be inactivated by phosphorylation, reducing acetyl CoA production.

Question 17

Which of the following is true regarding the F$$_1F$_o$$ ATP synthase complex?

Accepted Answer

Proton flow through F$$_o$$ causes rotation of the γ subunit within the α$$_3$$β$$_3$$ catalytic ring, resulting in ATP synthesis.

Question 18

Which of the following best describes the amphibolic nature of the citric acid cycle?

Accepted Answer

It functions in both catabolic and anabolic pathways, providing intermediates for biosynthesis and energy production.

Question 19

Which of the following is a consequence of incomplete reduction of oxygen by complexes I and III in the electron transport chain?

Accepted Answer

Generation of toxic superoxide anion (O$$_2^-) or $$hydrogen peroxide (H$$_2O$_2$$), contributing to cellular aging.

Chemotrophic Energy Metabolism: Aerobic Respiration (Chapter 10 Study Notes)

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