Question 1

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

Accepted Answer

Photosynthesis converts solar energy into chemical energy stored in glucose, while cellular respiration releases that energy for cellular work.

Question 2

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

Accepted Answer

Oxygen ($$O_2)$$

Question 3

Which stage of cellular respiration occurs in the cytosol and is responsible for breaking down glucose into pyruvate?

Accepted Answer

Glycolysis

Question 4

What is the net molecular product of glycolysis per molecule of glucose?

Accepted Answer

2 ATP, 2 NADH, and 2 pyruvate

Question 5

Which process in cellular respiration directly produces the most ATP?

Accepted Answer

Oxidative phosphorylation

Question 6

Why is oxygen essential for aerobic cellular respiration?

Accepted Answer

It serves as the final electron acceptor, allowing the electron transport chain to function.

Question 7

Which of the following best explains why brown fat cells generate heat instead of ATP?

Accepted Answer

They have a 'short circuit' in their electron transport chain that dissipates energy as heat.

Question 8

In the context of cellular respiration, what does the term 'substrate-level phosphorylation' refer to?

Accepted Answer

The direct transfer of a phosphate group from an organic molecule to ADP to form ATP.

Question 9

A runner inhales oxygen during exercise. Which statement best describes the fate of the oxygen atoms she inhales?

Accepted Answer

They accept electrons at the end of the electron transport chain and combine with hydrogen to form water.

Question 10

Which of the following equations correctly represents the overall process of cellular respiration?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + ATP$$

Question 11

Which stage of cellular respiration does NOT occur in the mitochondria?

Accepted Answer

Glycolysis

Question 12

During glycolysis, what is the role of NAD+?

Accepted Answer

It accepts electrons during the oxidation of glucose, becoming reduced to NADH.

Question 13

Which of the following best explains why sweating and other body-cooling mechanisms are necessary during vigorous exercise?

Accepted Answer

Cellular respiration releases heat as a byproduct, and the body must dissipate this excess heat.

Question 14

Which of the following is a correct description of the energy investment phase of glycolysis?

Accepted Answer

ATP is consumed to add phosphate groups to glucose, priming it for breakdown.

Question 15

If a person consumes a slice of pizza containing 475 kcal, how does the body primarily use this energy?

Accepted Answer

It is used for body maintenance and voluntary activities, with excess stored as fat.

Question 16

Which of the following is a real-world consequence of the exergonic nature of cellular respiration?

Accepted Answer

Cells release energy from glucose, capturing some as ATP and losing the rest as heat.

Question 17

Which of the following best describes the role of the electron transport chain in cellular respiration?

Accepted Answer

It transfers electrons from NADH and FADH2 to oxygen, generating a proton gradient for ATP synthesis.

Question 18

Which chemical characteristic of oxygen makes it suitable as the final electron acceptor in cellular respiration?

Accepted Answer

Its high electronegativity enables it to attract and accept electrons efficiently.

Question 19

In glycolysis, what is the significance of metabolic intermediates?

Accepted Answer

They serve as reactants for subsequent steps, allowing the pathway to proceed in a controlled sequence.

Question 20

Which of the following best describes the fate of electrons removed from fuel molecules during cellular respiration?

Accepted Answer

They are transferred to NAD+, forming NADH, and eventually passed to oxygen to form water.

Cellular Respiration: How Cells Harvest Chemical Energy

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