Question 1

Which of the following best describes the relationship between photosynthesis and cellular respiration?

Accepted Answer

Photosynthesis stores energy in organic molecules, while cellular respiration releases energy from organic molecules.

Question 2

During cellular respiration, which molecule is oxidized and which is reduced in the overall reaction $$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} ightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O} + 	ext{Energy}$$?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} is $$oxidized and $$\mathrm{O_2$} is $$reduced.

Question 3

Which of the following statements about redox reactions in cellular respiration is correct?

Accepted Answer

The substance that donates electrons is called the reducing agent.

Question 4

In the reaction $$\mathrm{Na} + \mathrm{Cl} \rightarrow \mathrm{Na^+} + \mathrm{Cl^-}$$, which statement is true?

Accepted Answer

Sodium is oxidized and acts as the reducing agent.

Question 5

Which of the following best explains why organic molecules with many hydrogen atoms are excellent fuels for cellular respiration?

Accepted Answer

The transfer of hydrogen (and its electrons) to oxygen releases energy that can be used to synthesize ATP.

Question 6

Which stage of cellular respiration produces the majority of ATP, and what is the main mechanism by which this ATP is generated?

Accepted Answer

Oxidative phosphorylation; chemiosmosis

Question 7

A patient is diagnosed with a mitochondrial disorder that impairs the function of the electron transport chain. Which of the following would most likely be observed in this patient’s cells?

Accepted Answer

Decreased ATP production due to impaired oxidative phosphorylation

Question 8

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

Accepted Answer

2 ATP and 2 NADH

Question 9

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

ATP is produced by the direct transfer of a phosphate group from a substrate to ADP by an enzyme.

Question 10

If oxygen is not present in a muscle cell, which process allows glycolysis to continue producing ATP?

Accepted Answer

Lactic acid fermentation regenerates NAD$$^+$$ from NADH.

Question 11

Which of the following is a correct summary of the energy investment and payoff phases of glycolysis?

Accepted Answer

The energy investment phase consumes 2 ATP, and the energy payoff phase produces 4 ATP and 2 NADH.

Question 12

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

Accepted Answer

Each turn of the cycle produces 1 ATP, 1 FADH$$_2$$, and 3 NADH, and the cycle turns twice per glucose molecule.

Question 13

Which of the following best explains why fats yield more ATP per gram than carbohydrates during cellular respiration?

Accepted Answer

Fats have more hydrogen atoms, providing more electrons for the electron transport chain.

Question 14

A researcher is studying a bacterium that uses sulfate ($$\mathrm{SO_4$^{2-}}) as $$its final electron acceptor instead of oxygen. Which process is this bacterium using?

Accepted Answer

Anaerobic respiration

Question 15

Which of the following is a key evolutionary significance of glycolysis?

Accepted Answer

It occurs in the cytosol and does not require oxygen, suggesting it evolved early in the history of life.

Question 16

Which of the following best describes the role of NAD$$^+ in $$cellular respiration?

Accepted Answer

NAD$$^+$$ acts as an electron carrier, accepting electrons and becoming reduced to NADH.

Question 17

Which of the following statements about chemiosmosis is correct?

Accepted Answer

Chemiosmosis is the process by which a proton gradient across the inner mitochondrial membrane drives ATP synthesis via ATP synthase.

Question 18

A person is exercising intensely and their muscle cells begin to produce lactate. What is the primary reason for this shift?

Accepted Answer

The rate of glycolysis exceeds the capacity of mitochondria to process pyruvate, leading to lactic acid fermentation.

Question 19

Which of the following is a correct comparison between fermentation and aerobic respiration?

Accepted Answer

Both processes use glycolysis to oxidize glucose to pyruvate.

Cellular Respiration: Pathways, Redox Reactions, and Glycolysis

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