Q: Which of the following equations correctly represents the overall chemical reaction for aerobic cellular respiration?

$$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} \rightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O} + \text{energy (ATP + heat)}$$

Question 1

Which of the following best describes the relationship between free energy change ($$\Delta G) $$and the direction of a chemical reaction at constant temperature and pressure?

Accepted Answer

A reaction with $$\Delta G \u003c 0$$ will proceed spontaneously in the forward direction.

Question 2

During cellular respiration, which molecule acts as the final electron acceptor in the electron transport chain, and what is the result of this process?

Accepted Answer

Oxygen; it combines with electrons and protons to form water.

Question 3

Which of the following equations correctly represents the overall chemical reaction for aerobic cellular respiration?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} ightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O} + 	ext{energy (ATP + heat)}$$

Question 4

Which of the following best explains why ATP is considered the 'energy currency' of the cell?

Accepted Answer

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

Question 5

Which of the following statements about glycolysis is correct?

Accepted Answer

Glycolysis occurs in the cytoplasm and produces a net gain of 2 ATP per glucose molecule.

Question 6

If a poison inhibits the function of ATP synthase, which stage of cellular respiration would be directly affected, and what would be the immediate consequence?

Accepted Answer

Oxidative phosphorylation; ATP production would decrease significantly.

Question 7

During fermentation, which of the following occurs when oxygen is not available to a muscle cell?

Accepted Answer

Pyruvate is converted to lactate, regenerating NAD+ for glycolysis.

Question 8

Which of the following best describes the role of NAD+ in cellular respiration?

Accepted Answer

NAD+ acts as an electron carrier, accepting electrons during glycolysis and the citric acid cycle.

Question 9

A cell is exposed to cyanide, which blocks the transfer of electrons to oxygen in the electron transport chain. What is the most immediate effect on ATP production?

Accepted Answer

ATP synthesis by oxidative phosphorylation stops, leading to rapid cell death.

Question 10

Which of the following is a correct sequence of events for the flow of electrons during aerobic cellular respiration?

Accepted Answer

Glucose $$\rightarrow$$ NADH $$\rightarrow$$ electron transport chain $$\rightarrow O2$$

Question 11

Which of the following best explains why the citric acid cycle is considered a central hub of metabolism?

Accepted Answer

It oxidizes acetyl-CoA, producing NADH and FADH2, and provides intermediates for biosynthetic pathways.

Question 12

A mutation causes a defect in the mitochondrial inner membrane, making it leaky to protons. What is the most likely effect on ATP synthesis?

Accepted Answer

The proton gradient would dissipate, reducing ATP synthesis by chemiosmosis.

Question 13

Which of the following is an example of substrate-level phosphorylation?

Accepted Answer

The direct transfer of a phosphate group from phosphoenolpyruvate to ADP during glycolysis.

Question 14

If a cell's supply of NAD+ is depleted, which process will be most immediately affected?

Accepted Answer

Glycolysis, because NAD+ is required to accept electrons during the oxidation of glyceraldehyde-3-phosphate.

Question 15

Which of the following best describes the effect of reaching chemical equilibrium in a metabolic pathway?

Accepted Answer

The forward and reverse reactions occur at the same rate, and no net change in reactant or product concentrations occurs.

Question 16

Which of the following scenarios best illustrates how altering one aspect of a metabolic pathway can affect upstream and downstream reactions?

Accepted Answer

Inhibition of an enzyme in glycolysis causes accumulation of upstream intermediates and reduces the flow of metabolites to the citric acid cycle.

Question 17

Which of the following is a key difference between aerobic respiration and fermentation?

Accepted Answer

Aerobic respiration uses oxygen as the final electron acceptor, while fermentation uses an organic molecule.

Question 18

Which of the following best explains why fats yield more ATP per gram than carbohydrates during cellular respiration?

Accepted Answer

Fats have more reduced carbon atoms, allowing for more oxidation and thus more NADH and FADH2 production.

Question 19

Which of the following best describes chemiosmosis in the context of cellular respiration?

Accepted Answer

The movement of protons down their electrochemical gradient through ATP synthase to drive ATP synthesis.

Cellular Respiration, Free Energy, and Metabolic Pathways: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard