Question 1

Which of the following best describes the chemiosmotic hypothesis in cellular energetics?

Accepted Answer

It states that the energy from electron transport is used to create a proton gradient across the inner mitochondrial membrane, which then drives ATP synthesis.

Question 2

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

Accepted Answer

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

Question 3

Which of the following is NOT a function of mitochondria listed in Table 12-1?

Accepted Answer

Synthesis of ribosomal RNA

Question 4

A patient has a genetic defect that impairs mitochondrial fission. Which cellular process is most likely to be directly affected?

Accepted Answer

Mitophagy of damaged mitochondria

Question 5

Which of the following statements about the citric acid cycle is correct?

Accepted Answer

It oxidizes acetyl CoA to CO$$_2$$ and generates NADH and FADH$$_2.$$

Question 6

Which complex in the electron transport chain is responsible for reducing O$$_2 to H$_2O$$?

Accepted Answer

Complex IV (Cytochrome c oxidase)

Question 7

What is the immediate source of energy for ATP synthesis by ATP synthase in mitochondria?

Accepted Answer

The proton-motive force across the inner mitochondrial membrane

Question 8

In the absence of oxygen, how do cells regenerate NAD$$^+ to $$allow glycolysis to continue?

Accepted Answer

By converting pyruvate to lactic acid or ethanol

Question 9

Which of the following best explains why C$$_4$$ plants are more efficient than C$$_3$$ plants under hot, dry conditions?

Accepted Answer

C$$_4$$ plants concentrate CO$$_2 in $$bundle sheath cells, reducing photorespiration.

Question 10

Which of the following is a correct description of the role of membrane contact sites (MCSs) in mitochondria?

Accepted Answer

They facilitate direct transfer of lipids and calcium between mitochondria and other organelles.

Question 11

Which of the following is the correct net equation for aerobic glucose metabolism in muscle cells?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} + 6\,\mathrm{O_2$} \rightarrow 6\,\mathrm{CO_2$} + 6\,\mathrm{H_2O} + 30-32\,\mathrm{ATP}$$

Question 12

Which prosthetic group is NOT permanently bound to a protein complex in the electron transport chain?

Accepted Answer

Coenzyme Q (ubiquinone)

Question 13

A mutation impairs the function of cytochrome c. Which process would be most directly affected?

Accepted Answer

Transfer of electrons from complex III to complex IV in the electron transport chain

Question 14

Which of the following best explains why the oxidation of very long chain fatty acids occurs primarily in peroxisomes rather than mitochondria?

Accepted Answer

Mitochondria cannot accommodate very long chain fatty acids for initial oxidation.

Question 15

Which of the following is a direct product of the light reactions of photosynthesis in chloroplasts?

Accepted Answer

NADPH and ATP

Question 16

Which of the following is a consequence of defective mitophagy in a cell?

Accepted Answer

Accumulation of damaged mitochondria and increased oxidative stress

Question 17

Which of the following best describes the role of the F$$_0F$_1$$ ATP synthase complex?

Accepted Answer

It uses the energy of the proton-motive force to catalyze the synthesis of ATP from ADP and inorganic phosphate.

Question 18

Which of the following is a key difference between the electron transport chains of mitochondria and chloroplasts?

Accepted Answer

Mitochondria use O$$_2 as $$the terminal electron acceptor, while chloroplasts use NADP$$^+.$$

Cellular Energetics: Chemiosmosis, Glycolysis, Mitochondria, Electron Transport, and Photosynthesis

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