Question 1

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

Accepted Answer

It proposes that the energy from electron transport is used to create a proton gradient across a 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

Protein translation in the cytosol

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

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

What is the primary role of the electron transport chain in mitochondria?

Accepted Answer

To generate a proton-motive force by transferring electrons from NADH and FADH$$_2 to O$_2.$$

Question 7

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 the initial steps of very long chain fatty acid oxidation.

Question 8

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

Accepted Answer

O$$_2$$

Question 9

In the Calvin cycle, what is the main function of ATP and NADPH?

Accepted Answer

To fix CO$$_2$$ into organic molecules

Question 10

Which of the following best describes the fate of pyruvate under anaerobic conditions in muscle cells?

Accepted Answer

It is converted to lactic acid to regenerate NAD$$^+.$$

Question 11

Which of the following is a key regulatory enzyme in glycolysis that is allosterically inhibited by high levels of ATP?

Accepted Answer

Phosphofructokinase-1

Question 12

A mutation in the gene encoding cytochrome c oxidase (complex IV) would most directly impair which process?

Accepted Answer

Reduction of O$$_2 to H$_2O$$

Question 13

Which of the following is a consequence of photorespiration in C$$_3$$ plants?

Accepted Answer

Loss of fixed CO$$_2$$ and decreased photosynthetic efficiency

Question 14

Which of the following statements about the endosymbiont hypothesis is correct?

Accepted Answer

Mitochondria and chloroplasts evolved from bacteria that formed a symbiotic relationship with ancestral eukaryotic cells.

Question 15

Which of the following best explains why brown fat mitochondria are specialized for thermogenesis?

Accepted Answer

They contain uncoupling proteins that dissipate the proton-motive force as heat instead of producing ATP.

Question 16

Which of the following is a direct result of the proton-motive force across the inner mitochondrial membrane?

Accepted Answer

Synthesis of ATP by ATP synthase

Question 17

Which of the following is a unique feature of C$$_4$$ plants compared to C$$_3$$ plants?

Accepted Answer

They fix CO$$_2 in $$mesophyll cells into four-carbon molecules that are shuttled to bundle sheath cells.

Question 18

Which of the following is a function of mitochondrial membrane contact sites (MCSs)?

Accepted Answer

Facilitate calcium transport and energy metabolism

Question 19

Which of the following best describes the role of NADH and FADH$$_2 in $$cellular respiration?

Accepted Answer

They donate high-energy electrons to the electron transport chain, driving the generation of a proton gradient.

Question 20

Which of the following is a likely consequence of a defect in mitophagy?

Accepted Answer

Accumulation of damaged mitochondria and increased oxidative stress

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

Guida di studio - Domande di pratica