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

Question 1

Which of the following statements best explains why ATP is considered an intermediate in phosphorylation potential among phosphorylated molecules?

Accepted Answer

ATP can serve as both a phosphate donor and acceptor, allowing it to couple exergonic and endergonic reactions.

Question 2

During cellular respiration, which molecule acts as the final electron acceptor in the electron transport chain?

Accepted Answer

O$$_2$$

Question 3

Which process produces the greatest net yield of ATP per molecule of glucose?

Accepted Answer

Aerobic cellular respiration

Question 4

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

Accepted Answer

They are electron carriers that donate electrons to the electron transport chain.

Question 5

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

Accepted Answer

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

Question 6

Why is fermentation necessary in the absence of oxygen for facultative anaerobes?

Accepted Answer

It regenerates NAD$$^+ so $$glycolysis can continue to produce ATP.

Question 7

Which of the following best describes the energy coupling that occurs during ATP hydrolysis?

Accepted Answer

ATP hydrolysis releases energy that can drive endergonic cellular processes.

Question 8

Which step in glucose oxidation is directly regulated by feedback inhibition from ATP?

Accepted Answer

The third step of glycolysis catalyzed by phosphofructokinase (PFK)

Question 9

Which of the following statements about substrate-level phosphorylation is correct?

Accepted Answer

It involves the direct transfer of a phosphate group from a high-energy substrate to ADP.

Question 10

A patient’s muscle cells are deprived of oxygen. Which metabolic pathway will allow the cells to continue producing ATP?

Accepted Answer

Lactic acid fermentation

Question 11

Which of the following best explains why fats are considered better fuels than carbohydrates on a per gram basis?

Accepted Answer

Fats contain more non-polar covalent bonds, which store more chemical energy.

Question 12

Which of the following is a correct description of an exergonic reaction?

Accepted Answer

It releases energy and has a negative $$\Delta G.$$

Question 13

Which of the following is true regarding the regulation of phosphofructokinase (PFK) in glycolysis?

Accepted Answer

High levels of ATP inhibit PFK by binding to its regulatory site.

Question 14

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

Accepted Answer

It is converted to acetaldehyde and then to ethanol.

Question 15

Which of the following statements about redox reactions is correct?

Accepted Answer

Oxidation and reduction always occur together in a chemical reaction.

Question 16

Which of the following is a direct product of the citric acid cycle per glucose molecule?

Accepted Answer

6 NADH

Question 17

What is the main function of the electron transport chain in mitochondria?

Accepted Answer

To create a proton gradient that drives ATP synthesis via ATP synthase

Question 18

Which of the following best explains why glycolysis is considered one of the most ancient metabolic pathways?

Accepted Answer

It occurs in almost all organisms and does not require organelles or oxygen.

Question 19

Which of the following is a correct summary of the energy yield from glycolysis per molecule of glucose?

Accepted Answer

2 ATP (net), 2 NADH, 2 pyruvate

Question 20

Which of the following best describes the role of phosphorylation in regulating protein activity?

Accepted Answer

Phosphorylation can change the shape and activity of proteins, either activating or inactivating them.

Cellular Energy Metabolism: Cellular Respiration, Fermentation, and Energy Coupling

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