Question 1

The primary function of the electron transport chain and oxidative phosphorylation is which of the following?

Accepted Answer

The primary function of the electron transport chain and oxidative phosphorylation is to oxidize the reduced coenzymes NADH and FADH2, which are produced in earlier stages of cellular respiration, and use the energy released to synthesize ATP. This process is known as oxidative phosphorylation. Choice A is incorrect because the electron transport chain does not provide electrons and energy for the phosphorylation of ATP, but rather uses electrons from NADH and FADH2 to create an electrochemical gradient that drives ATP synthesis. Choice B is incorrect because the reduced coenzymes are not synthesized for digestion, but rather are used in cellular respiration. Choice D is incorrect because the electron transport chain does not transport electrons from ATP to ADP, but rather from NADH and FADH2 to oxygen.

Question 2

Coenzyme A is a biological oxidizing agent used to convert alcohols to carbonyl-containing compounds.

Accepted Answer

Coenzyme A is involved in the synthesis and oxidation of fatty acids, and the oxidation of pyruvate in the citric acid cycle, but it is not directly used as an oxidizing agent to convert alcohols to carbonyl-containing compounds.

Question 3

Step 7 of the citric acid cycle is shown. Which statement best describes what occurs in this step?

Accepted Answer

In step 7 of the citric acid cycle, fumarate undergoes hydration with the aid of the enzyme fumarase, forming malate. This step is important for generating energy in the form of NADH and FADH2, which will be used in the electron transport chain to produce ATP.

Question 4

Step 7 of the citric acid cycle is shown. Which statement best describes what occurs in this step?

Accepted Answer

In step 7 of the citric acid cycle, fumarate undergoes hydration with the aid of the enzyme fumarase, forming malate. This step is also known as the hydration of fumarate.

Question 5

The final stage of the electron transport chain forms water in an anaerobic process.

Accepted Answer

The final stage of the electron transport chain in aerobic respiration forms water, but in anaerobic respiration, the final electron acceptor is not oxygen and therefore water is not formed. Instead, different molecules such as sulfur or nitrate may be used as the final electron acceptor, leading to the formation of different end products.

Question 6

Energy released from H⁺ movement in the electron transport chain fuels the phosphorylation of ADP.

Accepted Answer

The movement of electrons from H^to in the electron transport chain releases energy that is used to fuel the phosphorylation of ADP to ATP in oxidative phosphorylation.

Question 7

Oxaloacetate is the starting material in the first step of the citric acid cycle and the product of the last step. The last step of the citric acid cycle, the oxidation of malate to oxaloacetate, is shown. What is the structure of oxaloacetate?

Accepted Answer

The answer of Oxaloacetate is the starting material in the...

Question 8

Which statement best describes how the interconversion of ATP and ADP is responsible for storing and providing energy for cellular reactions?

Accepted Answer

The interconversion of ATP and ADP is responsible for storing and providing energy for cellular reactions because the energy required to phosphorylate ADP to ATP is stored in ATP, and this stored energy is released when ATP undergoes hydrolysis to ADP. This process provides energy for cellular reactions.

Question 9

Oxaloacetate is the starting material in the first step of the citric acid cycle and the product of the last step. The last step of the citric acid cycle, the oxidation of malate to oxaloacetate, is shown. What is the structure of oxaloacetate?

Accepted Answer

The answer of Oxaloacetate is the starting material in the...

Question 10

The terms phosphorylation and oxidative phosphorylation may be used interchangeably.

Accepted Answer

Phosphorylation is the addition of a phosphate group to a molecule, while oxidative phosphorylation is the process by which ATP is synthesized using energy released by the electron transport chain. These terms are not interchangeable.

Question 11

Coenzyme A is synthesized in cells from pantothenic acid, vitamin B₅.

Accepted Answer

Coenzyme A is synthesized in cells from pantothenic acid, which is also known as vitamin B5.

Question 12

The conversion of Fe³⁺ to Fe²⁺ in the electron transport chain is an example of Fe³⁺ acting as an oxidizing agent.

Accepted Answer

The oxidation process involves the loss of electrons, which are transferred to an oxidizing agent. In this case, FeS1U1P13 acts as the oxidizing agent as it accepts electrons, while S1U1P13 acts as the reducing agent as it donates electrons. Therefore, the conversion of FeS1U1P13+S1S1P0 to FeS1U1P12+S1S1P0 is an example of FeS1U1P13+S1S1P0 acting as an oxidizing agent.

Question 13

The citric acid cycle is also called the tricarboxylic acid cycle (TCA cycle).

Accepted Answer

The citric acid cycle is also known as the tricarboxylic acid cycle or the Krebs cycle.

Question 14

In the electron transport chain, H⁺ ions are pumped across the inner membrane of the mitochondrion, forming a high concentration of H⁺ ions in the intermembrane space, thus creating a potential energy gradient.

Accepted Answer

This is a correct statement about the electron transport chain in mitochondria. The pumping of H⁺ ions across the inner membrane creates a gradient of ions that can be used to produce ATP through the action of ATP synthase. This process is a key part of oxidative phosphorylation, which generates the majority of the ATP produced by cells.

Question 15

All steps of the citric acid cycle are enzyme catalyzed.

Accepted Answer

All reactions in the citric acid cycle, also known as the Krebs cycle, are enzyme catalyzed. It involves a series of eight enzymatic reactions that ultimately produce ATP, NADH, and FADH2.

Question 16

NAD⁺is the abbreviation for nicotinamide adenine dinucleotide.

Accepted Answer

The answer of NAD⁺is the abbreviation for nicotinamide adenine...

Question 17

The electron transport chain is a multistep process that relies on five enzyme systems as well as mobile electron carriers.

Accepted Answer

The answer of The electron transport chain is a multistep...

Question 18

Since more energy is released from the hydrolysis of creatine phosphate than is needed for the phosphorylation of ADP, the coupling of these two reactions results in the formation of ATP from ADP.

Accepted Answer

This statement is true. The energy released from the hydrolysis of creatine phosphate is used to phosphorylate ADP, resulting in the formation of ATP. This process is essential for providing energy to muscle cells during high-intensity exercise.

Question 19

The citric acid cycle comprises stage [4] of metabolism.

Accepted Answer

The citric acid cycle is considered stage 3 of cellular metabolism, following glycolysis (stage 1) and the pyruvate oxidation/acyl-CoA synthesis (stage 2).

Question 20

H⁺ ions generated by reactions in the electron transport chain, as well as H⁺ ions present in the matrix of the mitochondria, are pumped across the inner mitochondrial membrane into the intermembrane space at three different sites.

Accepted Answer

H⁺ ions are pumped across the inner mitochondrial membrane into the intermembrane space at three different sites in the electron transport chain. Additionally, some H⁺ ions present in the mitochondrial matrix can also be pumped out.

Quiz 23: Digestion and the Conversion of Food Into Energy

The primary function of the electron transport chain and oxidative phosphorylation is which of the following?

Coenzyme A is a biological oxidizing agent used to convert alcohols to carbonyl-containing compounds.

Step 7 of the citric acid cycle is shown. Which statement best describes what occurs in this step?

Step 7 of the citric acid cycle is shown. Which statement best describes what occurs in this step?

The final stage of the electron transport chain forms water in an anaerobic process.

Energy released from H+ movement in the electron transport chain fuels the phosphorylation of ADP.

Oxaloacetate is the starting material in the first step of the citric acid cycle and the product of the last step. The last step of the citric acid cycle, the oxidation of malate to oxaloacetate, is shown. What is the structure of oxaloacetate?

Which statement best describes how the interconversion of ATP and ADP is responsible for storing and providing energy for cellular reactions?

Oxaloacetate is the starting material in the first step of the citric acid cycle and the product of the last step. The last step of the citric acid cycle, the oxidation of malate to oxaloacetate, is shown. What is the structure of oxaloacetate?

The terms phosphorylation and oxidative phosphorylation may be used interchangeably.

Coenzyme A is synthesized in cells from pantothenic acid, vitamin B5.

The conversion of Fe3+ to Fe2+ in the electron transport chain is an example of Fe3+ acting as an oxidizing agent.

The citric acid cycle is also called the tricarboxylic acid cycle (TCA cycle).

In the electron transport chain, H+ ions are pumped across the inner membrane of the mitochondrion, forming a high concentration of H+ ions in the intermembrane space, thus creating a potential energy gradient.

All steps of the citric acid cycle are enzyme catalyzed.

NAD+ is the abbreviation for nicotinamide adenine dinucleotide.

The electron transport chain is a multistep process that relies on five enzyme systems as well as mobile electron carriers.

Since more energy is released from the hydrolysis of creatine phosphate than is needed for the phosphorylation of ADP, the coupling of these two reactions results in the formation of ATP from ADP.

The citric acid cycle comprises stage [4] of metabolism.

H+ ions generated by reactions in the electron transport chain, as well as H+ ions present in the matrix of the mitochondria, are pumped across the inner mitochondrial membrane into the intermembrane space at three different sites.

Energy released from H⁺ movement in the electron transport chain fuels the phosphorylation of ADP.

Coenzyme A is synthesized in cells from pantothenic acid, vitamin B₅.

The conversion of Fe³⁺ to Fe²⁺ in the electron transport chain is an example of Fe³⁺ acting as an oxidizing agent.

In the electron transport chain, H⁺ ions are pumped across the inner membrane of the mitochondrion, forming a high concentration of H⁺ ions in the intermembrane space, thus creating a potential energy gradient.

NAD⁺is the abbreviation for nicotinamide adenine dinucleotide.

H⁺ ions generated by reactions in the electron transport chain, as well as H⁺ ions present in the matrix of the mitochondria, are pumped across the inner mitochondrial membrane into the intermembrane space at three different sites.