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

Question 1

Which of the following best describes the overall equation for aerobic cellular respiration in eukaryotic cells?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} + \mathrm{O_2$} ightarrow \mathrm{CO_2$} + \mathrm{H_2O} + 	ext{Energy}$$

Question 2

During glycolysis, which enzyme catalyzes the rate-limiting step, and what is its primary regulatory molecule?

Accepted Answer

Phosphofructokinase-1; regulated by ATP

Question 3

Which of the following is NOT a net product of glycolysis from one molecule of glucose?

Accepted Answer

2 molecules of FADH$$_2$$

Question 4

In anaerobic conditions, muscle cells convert pyruvate to lactate. What is the primary purpose of this conversion?

Accepted Answer

To regenerate NAD$$^+$$ for continued glycolysis

Question 5

Which metabolic pathway is responsible for the breakdown of fatty acids into Acetyl-CoA?

Accepted Answer

$$\beta-$$oxidation

Question 6

What is the main function of the TCA (Krebs) cycle in cellular respiration?

Accepted Answer

To generate high-energy electron carriers (NADH and FADH$$_2)$$

Question 7

Which statement best explains the movement of electrons in the mitochondrial electron transport chain?

Accepted Answer

Electrons move spontaneously from a pair with low redox potential (NADH/NAD$$^+) to a $$pair with high redox potential (O$$_2/H$_2O)$$

Question 8

What is the role of the proton-motive force in mitochondria?

Accepted Answer

It drives the synthesis of ATP via chemiosmotic coupling

Question 9

Which of the following best describes chemiosmotic coupling?

Accepted Answer

The use of a proton gradient across the inner mitochondrial membrane to drive ATP synthesis

Question 10

A patient takes dinitrophenol (DNP), a mitochondrial uncoupler. What is the most likely physiological consequence?

Accepted Answer

Loss of ATP production and increased heat generation

Question 11

Which of the following correctly matches the location of each process in eukaryotic cells?

Accepted Answer

Glycolysis: cytosol; TCA cycle: mitochondrial matrix; Electron transport chain: inner mitochondrial membrane

Question 12

Which molecule is the final electron acceptor in the mitochondrial electron transport chain?

Accepted Answer

O$$_2$$

Question 13

If a cell is deprived of oxygen, which process will be directly inhibited?

Accepted Answer

Oxidative phosphorylation

Question 14

Which of the following statements about redox potentials in the electron transport chain is correct?

Accepted Answer

Redox potential increases along the electron transport chain, allowing electrons to flow toward oxygen

Question 15

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

Accepted Answer

Oxidative phosphorylation

Question 16

Which of the following is a direct result of the electron transport chain pumping protons into the intermembrane space?

Accepted Answer

Creation of an electrochemical gradient (proton-motive force)

Question 17

Which of the following best explains why NADH is considered a high-energy electron carrier?

Accepted Answer

It stores electrons with low redox potential that can be transferred to molecules with higher redox potential, releasing energy

Question 18

Which of the following is a multi-step process that integrates glycolysis, the TCA cycle, and oxidative phosphorylation?

Accepted Answer

Complete aerobic cellular respiration of glucose

Question 19

A mutation causes phosphofructokinase-1 to be insensitive to ATP levels. What is the most likely metabolic consequence?

Accepted Answer

Glycolysis will proceed unchecked, potentially leading to excessive ATP and pyruvate production

Question 20

Which of the following best describes the fate of Acetyl-CoA produced from the breakdown of carbohydrates, fats, and proteins?

Accepted Answer

It enters the TCA cycle for further oxidation and energy production

Cellular Respiration: Glycolysis, TCA Cycle, Redox Potentials, and Chemiosmotic Coupling

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