Q: Which of the following is a correct representation of the overall reaction for glucose oxidation?

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

Q: Which of the following is the correct efficiency calculation for ATP synthesis during glucose oxidation, given that 38 ATP are produced and each ATP stores 7 kcal/mole, while the total energy released is 686 kcal/mole?

$$\text{Efficiency} = \frac{266\ \text{kcal}}{686\ \text{kcal}} \approx 38.8\%$$

Question 1

Which of the following best describes the difference between catabolic and anabolic reactions in cellular metabolism?

Accepted Answer

Catabolic reactions break down larger molecules into smaller ones, releasing energy, while anabolic reactions synthesize larger molecules from smaller ones, requiring energy input.

Question 2

According to the first law of thermodynamics, which of the following statements is true regarding energy in biological systems?

Accepted Answer

Energy can be neither created nor destroyed, but it can change forms.

Question 3

A reaction in which the products have more energy than the reactants is called:

Accepted Answer

Endergonic reaction

Question 4

Which of the following best explains why enzymes are necessary for many biochemical reactions?

Accepted Answer

Enzymes lower the activation energy barrier, increasing the rate of reaction without being consumed.

Question 5

Which of the following is a correct representation of the overall reaction for glucose oxidation?

Accepted Answer

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

Question 6

During glycolysis, what is the net gain of ATP and NADH molecules per molecule of glucose?

Accepted Answer

2 ATP and 2 NADH

Question 7

Which of the following statements about the electron transport chain (ETC) is correct?

Accepted Answer

The ETC uses the energy from electrons to pump protons across the inner mitochondrial membrane, creating a gradient used to synthesize ATP.

Question 8

If oxygen is not available, which process allows glycolysis to continue by regenerating NAD$$^+$$?

Accepted Answer

Lactate fermentation

Question 9

Which of the following best describes the role of ATP in cellular metabolism?

Accepted Answer

ATP acts as the energy currency of the cell, providing readily accessible energy for cellular processes.

Question 10

A patient is experiencing muscle fatigue during intense exercise. Which metabolic pathway is most likely providing ATP to the muscle cells under these anaerobic conditions?

Accepted Answer

Lactate fermentation

Question 11

Which of the following is the correct efficiency calculation for ATP synthesis during glucose oxidation, given that 38 ATP are produced and each ATP stores 7 kcal/mole, while the total energy released is 686 kcal/mole?

Accepted Answer

$$	ext{Efficiency} = \frac{266\ 	ext{kcal}}{686\ 	ext{kcal}} \approx 38.8\%$$

Question 12

Which of the following statements about enzyme regulation is correct?

Accepted Answer

Covalent regulation often involves the addition or removal of a phosphate group, changing the enzyme's activity.

Question 13

Which molecule acts as the final electron acceptor in the electron transport chain during aerobic respiration?

Accepted Answer

O$$_2$$

Question 14

A person is fasting and has low carbohydrate intake. Which process allows the liver to synthesize new glucose from non-carbohydrate sources?

Accepted Answer

Gluconeogenesis

Question 15

Which of the following best explains why lipids provide more energy per gram than carbohydrates or proteins?

Accepted Answer

Lipids have longer carbon chains and more reduced bonds, storing more chemical energy.

Question 16

Which of the following is a correct example of a redox reaction in cellular metabolism?

Accepted Answer

NADH donates electrons to the electron transport chain and becomes NAD$$^+ ($$oxidation), while O$$_2$$ accepts electrons and is reduced to H$$_2O.$$

Question 17

Which of the following factors would NOT increase the rate of an enzyme-catalyzed reaction?

Accepted Answer

Decreasing enzyme concentration

Question 18

A patient with a genetic deficiency in glucose-6-phosphatase would have difficulty with which metabolic process?

Accepted Answer

Glycogenolysis in the liver

Question 19

Which of the following best describes the law of mass action as it applies to metabolic reactions?

Accepted Answer

Increasing reactant concentration pushes the reaction forward, while increasing product concentration pushes the reaction in reverse.

Question 20

Which of the following is a correct summary of ATP production from one molecule of glucose under aerobic conditions?

Accepted Answer

2 ATP from glycolysis, 2 ATP from Krebs cycle, and about 34 ATP from oxidative phosphorylation, totaling approximately 38 ATP

Cell Metabolism: Foundations of Energy Transformation in Human Physiology

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