Question 1

Which of the following terms describes metabolic pathways that break down complex molecules to release stored energy?

Accepted Answer

Catabolic pathways involve the breakdown of complex molecules, such as carbohydrates, fats, and proteins, releasing stored energy. Anabolic pathways, on the other hand, involve the synthesis of complex molecules from smaller building blocks, requiring energy input. Bioenergetic pathways and endergonic pathways are broader terms that encompass both catabolic and anabolic pathways, as well as the transfer and utilization of energy in living systems.

Question 2

Which of the following indicates a primary path by which electrons travel downhill energetically during aerobic respiration?

Accepted Answer

The primary path by which electrons travel downhill energetically during aerobic respiration is from glucose to NADH, then to the electron transport chain, and finally to oxygen, which is the final electron acceptor. This process generates a proton gradient that drives ATP synthesis. Option B correctly shows this sequence of events. The other options contain some incorrect or incomplete steps in the pathway.

Question 3

Which of the following metabolic processes in eukaryotic cells will proceed normally whether oxygen (O₂)is present or absent?

Accepted Answer

Glycolysis is an anaerobic process that does not require oxygen and can occur in the absence of oxygen. The other processes listed (electron transport, the citric acid cycle, oxidative phosphorylation, and chemiosmosis) all require oxygen for optimal functioning.

Question 4

As a result of an oxidation-reduction reaction,how is the oxidizing agent changed?

Accepted Answer

The oxidizing agent gains electrons during a redox reaction, which results in an increase in its potential energy.

Question 5

Approximately what percentage of the ATP formed by the reactions of glycolysis is produced by substrate-level phosphorylation?

Accepted Answer

100% of the ATP formed by the reactions of glycolysis is produced by substrate-level phosphorylation, as glycolysis does not involve oxidative phosphorylation, which occurs later in cellular respiration.

Question 6

When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction,the glucose molecule becomes

Accepted Answer

When a glucose molecule loses a hydrogen atom, it means that it has lost an electron. This type of reaction is called oxidation. Therefore, the glucose molecule is oxidized.

Question 7

The complete reactions of cellular respiration in the presence of oxygen (C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + energy)result in which of the following?

Accepted Answer

The complete reactions of cellular respiration in the presence of oxygen involve the oxidation of glucose (C₆H₁₂O₆) and reduction of oxygen (6 O₂), resulting in the production of carbon dioxide (6 CO₂) and water (6 H₂O) along with energy in the form of ATP. Therefore, the best choice is B which states that oxidation of glucose occurs along with reduction of oxygen.

Question 8

The oxygen consumed during cellular respiration is involved directly in which process or event?

Accepted Answer

Oxygen serves as the final electron acceptor at the end of the electron transport chain, which allows for the production of ATP through oxidative phosphorylation. Without oxygen, the electron transport chain would not be able to function, and cellular respiration would halt.

Question 9

Why are carbohydrates and fats considered high-energy foods?

Accepted Answer

Carbohydrates and fats are considered high-energy foods because they have a large number of electrons associated with hydrogen. When these molecules are metabolized, the bonds between the carbon and hydrogen atoms are broken, releasing a significant amount of energy that can be used by the body.

Question 10

How many molecules of oxygen (O₂)are consumed by the complete oxidation of glucose (C₆H₁₂O₆)to carbon dioxide and water in aerobic respiration?

Accepted Answer

In the balanced chemical equation for the complete oxidation of glucose, C6H12O6 + 6O2 → 6CO2 + 6H2O, six molecules of oxygen (O2) are consumed.

Question 11

Where does glycolysis occur in animal cells?

Accepted Answer

Glycolysis occurs in the cytosol of animal cells.

Question 12

Which of the following statements about NAD⁺ is true?

Accepted Answer

NAD⁺ is reduced to NADH during glycolysis as it accepts electrons.

Question 13

Which chemical process generates the ATP produced in glycolysis?

Accepted Answer

Substrate-level phosphorylation is the chemical process that generates the ATP produced in glycolysis. This process involves the transfer of a phosphate group from a high-energy molecule, such as phosphoenolpyruvate or ADP, to ADP to form ATP. It does not require oxygen or the participation of an electron transport chain, unlike oxidative phosphorylation, and does not involve the production of a proton gradient for chemiosmosis. Photophosphorylation is a process that occurs in photosynthetic organisms, and electron transport is part of oxidative phosphorylation, but neither are directly involved in generating ATP in glycolysis.

Question 14

When a molecule of NAD⁺ (nicotinamide adenine dinucleotide)gains a hydrogen atom (not a proton),the NAD⁺ molecule becomes

Accepted Answer

When a molecule gains a hydrogen atom, it is essentially gaining an electron and a proton. This is a reduction reaction, meaning that the molecule is being reduced (the opposite of oxidized) and thus becoming more negatively charged. NAD+ (the oxidized form of NAD) is often reduced to NADH in biological processes.

Question 15

Which of the following situations results from the transfer of an electron to a more electronegative atom?

Accepted Answer

When an electron is transferred to a more electronegative atom, the electron is essentially moving closer to the positively charged nucleus of the more electronegative atom. This results in a decrease in potential energy for the electron.

Question 16

Approximately what percentage of the ATP formed by the electron transport chain is produced by substrate-level phosphorylation?

Accepted Answer

The ATP formed by the electron transport chain is produced by oxidative phosphorylation, not substrate-level phosphorylation, which means 0% of the ATP from the electron transport chain is produced by substrate-level phosphorylation.

Question 17

Which of the following describes the result of transferring an electron from a less electronegative atom to a more electronegative atom?

Accepted Answer

When an electron is transferred from a less electronegative atom to a more electronegative atom, the more electronegative atom gains an electron, which is a reduction process, and this transfer typically releases energy due to the stabilization that occurs when electrons move to more electronegative atoms.

Question 18

In an oxidation-reduction reaction,how is the reducing agent changed?

Accepted Answer

In an oxidation-reduction (redox) reaction, the reducing agent undergoes oxidation, meaning it loses electrons. As it loses electrons, it typically loses potential energy because the electrons, which carry energy, are transferred to another species.

Question 19

Which of the following sequences represents the correct order in which metabolic reactions occur during the complete oxidation of glucose through aerobic respiration?

Accepted Answer

The correct sequence for the complete oxidation of glucose in aerobic respiration is: glucose is first broken down into pyruvate through glycolysis, then pyruvate is oxidized to acetyl-CoA (pyruvate oxidation), which enters the citric acid cycle, and finally, the electrons transferred through carriers participate in the electron transport chain to produce ATP.

Question 20

Which chemical process generates the ATP produced in the citric acid cycle?

Accepted Answer

During the citric acid cycle, ATP is produced through substrate-level phosphorylation, where a phosphate group is transferred from a substrate molecule to ADP to produce ATP. This is in contrast to oxidative phosphorylation, which involves electron transport and chemiosmosis to generate ATP. Photophosphorylation also involves electron transport but occurs in photosynthetic organisms during the light-dependent reactions. Therefore, the correct answer is E) substrate-level phosphorylation.

Quiz 7: Cellular Respiration and Fermentation

Which of the following terms describes metabolic pathways that break down complex molecules to release stored energy?

Which of the following indicates a primary path by which electrons travel downhill energetically during aerobic respiration?

Which of the following metabolic processes in eukaryotic cells will proceed normally whether oxygen (O₂) is present or absent?

As a result of an oxidation-reduction reaction,how is the oxidizing agent changed?

Approximately what percentage of the ATP formed by the reactions of glycolysis is produced by substrate-level phosphorylation?

When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction,the glucose molecule becomes

The complete reactions of cellular respiration in the presence of oxygen (C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + energy) result in which of the following?

The oxygen consumed during cellular respiration is involved directly in which process or event?

Why are carbohydrates and fats considered high-energy foods?

How many molecules of oxygen (O₂) are consumed by the complete oxidation of glucose (C₆H₁₂O₆) to carbon dioxide and water in aerobic respiration?

Where does glycolysis occur in animal cells?

Which of the following statements about NAD⁺ is true?

Which chemical process generates the ATP produced in glycolysis?

When a molecule of NAD⁺ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton) ,the NAD⁺ molecule becomes

Which of the following situations results from the transfer of an electron to a more electronegative atom?

Approximately what percentage of the ATP formed by the electron transport chain is produced by substrate-level phosphorylation?

Which of the following describes the result of transferring an electron from a less electronegative atom to a more electronegative atom?

In an oxidation-reduction reaction,how is the reducing agent changed?

Which of the following sequences represents the correct order in which metabolic reactions occur during the complete oxidation of glucose through aerobic respiration?

Which chemical process generates the ATP produced in the citric acid cycle?

Quiz 7: Cellular Respiration and Fermentation

Which of the following terms describes metabolic pathways that break down complex molecules to release stored energy?

Which of the following indicates a primary path by which electrons travel downhill energetically during aerobic respiration?

Which of the following metabolic processes in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?

As a result of an oxidation-reduction reaction,how is the oxidizing agent changed?

Approximately what percentage of the ATP formed by the reactions of glycolysis is produced by substrate-level phosphorylation?

When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction,the glucose molecule becomes

The complete reactions of cellular respiration in the presence of oxygen (C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy) result in which of the following?

The oxygen consumed during cellular respiration is involved directly in which process or event?

Why are carbohydrates and fats considered high-energy foods?

How many molecules of oxygen (O2) are consumed by the complete oxidation of glucose (C6H12O6) to carbon dioxide and water in aerobic respiration?

Where does glycolysis occur in animal cells?

Which of the following statements about NAD+ is true?

Which chemical process generates the ATP produced in glycolysis?

When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton) ,the NAD+ molecule becomes

Which of the following situations results from the transfer of an electron to a more electronegative atom?

Approximately what percentage of the ATP formed by the electron transport chain is produced by substrate-level phosphorylation?

Which of the following describes the result of transferring an electron from a less electronegative atom to a more electronegative atom?

In an oxidation-reduction reaction,how is the reducing agent changed?

Which of the following sequences represents the correct order in which metabolic reactions occur during the complete oxidation of glucose through aerobic respiration?

Which chemical process generates the ATP produced in the citric acid cycle?

Which of the following metabolic processes in eukaryotic cells will proceed normally whether oxygen (O₂) is present or absent?

The complete reactions of cellular respiration in the presence of oxygen (C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + energy) result in which of the following?

How many molecules of oxygen (O₂) are consumed by the complete oxidation of glucose (C₆H₁₂O₆) to carbon dioxide and water in aerobic respiration?

Which of the following statements about NAD⁺ is true?

When a molecule of NAD⁺ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton) ,the NAD⁺ molecule becomes