Question 1

Which of the following best describes what happens to molecule A in the redox reaction shown in the first image?

Accepted Answer

Molecule A is oxidized because it loses an electron.

Question 2

Based on the glycolysis pathway shown in the second image, what is the net gain of ATP and NADH molecules per molecule of glucose?

Accepted Answer

$$2$$ ATP and $$2$$ NADH

Question 3

Refer to the third image. During glycolysis, why is ATP initially invested in the energy investment phase?

Accepted Answer

To phosphorylate glucose, making it more chemically reactive.

Question 4

According to the fourth image, what is the fate of pyruvate after it enters the mitochondrion in the presence of oxygen?

Accepted Answer

It is converted to acetyl-CoA, releasing CO$$_2$$ and producing NADH.

Question 5

In the fifth image, what is the role of oxaloacetate in the citric acid cycle?

Accepted Answer

It combines with acetyl-CoA to form citrate, starting the cycle.

Question 6

Based on the sixth image, which of the following is produced per turn of the citric acid cycle from one acetyl-CoA?

Accepted Answer

$$3$$ NADH, $$1$$ FADH$$_2$$, and $$1$$ ATP

Question 7

Refer to the seventh image. What is the primary function of the electron transport chain in mitochondria?

Accepted Answer

To transfer electrons from NADH and FADH$$_2 to $$oxygen, creating a proton gradient.

Question 8

In the eighth image, what is the significance of the cristae in mitochondria?

Accepted Answer

They increase the surface area for oxidative phosphorylation.

Question 9

Based on the ninth image, how does chemiosmosis contribute to ATP synthesis?

Accepted Answer

By using the flow of H$$^+$$ ions down their gradient through ATP synthase to drive ATP production.

Question 10

Refer to the tenth image. What determines whether pyruvate undergoes fermentation or enters the citric acid cycle?

Accepted Answer

The presence or absence of oxygen.

Question 11

According to the eleventh image, what is the final electron acceptor in alcohol fermentation?

Accepted Answer

Acetaldehyde

Question 12

Based on the twelfth image, which statement best describes what happens to sodium (Na) in the reaction shown?

Accepted Answer

Na is oxidized because it loses an electron.

Question 13

Refer to the thirteenth image. What is the end product of lactic acid fermentation?

Accepted Answer

Lactate

Question 14

Based on the fourteenth image, which macromolecules can enter cellular respiration at the level of glycolysis or the citric acid cycle?

Accepted Answer

Carbohydrates, proteins, and fats

Question 15

Refer to the fifteenth image. What is the role of phosphofructokinase in cellular respiration?

Accepted Answer

It acts as a key regulatory enzyme in glycolysis, responding to feedback from ATP and AMP.

Question 16

Based on the sixteenth image, what experimental change could increase the accumulation of acetyl-CoA in the reaction?

Accepted Answer

Increase the concentration of pyruvate.

Question 17

Refer to the seventeenth image. What is the main function of the electron transport chain in the mitochondria?

Accepted Answer

To pump protons (H$$^+) $$across the inner mitochondrial membrane, creating a proton gradient.

Question 18

Based on the eighteenth image, what is the effect of an uncoupling protein in brown fat mitochondria?

Accepted Answer

It allows protons to flow back into the matrix without generating ATP, releasing energy as heat.

Question 19

Refer to the nineteenth image. Which compound is oxidized and which is reduced in the reaction shown?

Accepted Answer

Compound A is oxidized; Compound B is reduced.

Question 20

Based on the twentieth image, what is the balanced equation for cellular respiration?

Accepted Answer

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

Cellular Respiration and Fermentation: Mechanisms and Regulation

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