Chapter 13, Problem 8Q

A.

Summary Introduction

To explain: During oxidation of sugar molecules taking place in the cell, all of the energy produced is in the form of heat.

Introduction: In cellular respiration, with the help of oxygen, cells break down the glucose molecule into simpler forms. From the oxidation of glucose water, carbon dioxide is exhaled with some chemical energy in the form of ATP and small amount of heat. The general reaction is ${\text{C}}_6{\text{H}}_{12}{\text{O}}_6\text{(glucose)}\text{+}{\text{6O}}_2\to {\text{6CO}}_2\text{ +}{\text{6H}}_2\text{O}\text{+}\text{energy}$.

Answer to Problem 8Q

Correct answer: Statement is incorrect.

Explanation of Solution

In the cell for metabolic process, it requires chemical energy in the form of ATP. If the total energy is released in the form of heat then the metabolic process is affected. Also, the reaction would be worthless for the cell.

Hence, the statement is incorrect.

B.

Summary Introduction

To explain: During oxidation of sugar molecules taking place in the cell, none of the produced energy is in the form of heat.

Introduction: In cellular respiration, with the help of oxygen, cells break down the glucose molecule into simpler forms. From the oxidation of glucose water, carbon dioxide is exhaled with some chemical energy in the form of ATP and small amount of heat. The general reaction is ${\text{C}}_6{\text{H}}_{12}{\text{O}}_6\text{(glucose)}\text{+}{\text{6O}}_2\to {\text{6CO}}_2\text{ +}{\text{6H}}_2\text{O}\text{+}\text{energy}$.

Answer to Problem 8Q

Correct answer: Statement is incorrect.

Explanation of Solution

In the cell during the energy conversion process, the randomness of molecules accomplished by releasing the heat and also no energy conversion process can be 100% efficient.

Hence, the statement is incorrect.

C.

Summary Introduction

To explain: The energy is produced by a process that involves in the oxidation of carbon atoms.

Introduction: In cellular respiration, with the help of oxygen, cells break down the glucose molecule into simpler forms. From the oxidation of glucose water, carbon dioxide is exhaled with some chemical energy in the form of ATP and small amount of heat. The general reaction is ${\text{C}}_6{\text{H}}_{12}{\text{O}}_6\text{(glucose)}\text{+}{\text{6O}}_2\to {\text{6CO}}_2\text{ +}{\text{6H}}_2\text{O}\text{+}\text{energy}$.

Answer to Problem 8Q

Correct answer: Statement is correct.

Explanation of Solution

In the process of breakdown of glucose, the carbon atoms present in glucose are in reduced state compared to CO₂. The carbon atom of glucose is oxidized in the presence of oxygen.

Hence, the statement is correct.

D.

Summary Introduction

To explain: The reaction consisting of oxidation of sugar molecules supplies the cell with essential water.

Introduction: In cellular respiration, with the help of oxygen, cells break down the glucose molecule into simpler forms. From the oxidation of glucose water, carbon dioxide is exhaled with some chemical energy in the form of ATP and small amount of heat. The general reaction is ${\text{C}}_6{\text{H}}_{12}{\text{O}}_6\text{(glucose)}\text{+}{\text{6O}}_2\to {\text{6CO}}_2\text{ +}{\text{6H}}_2\text{O}\text{+}\text{energy}$.

Answer to Problem 8Q

Correct answer: Statement is incorrect.

Explanation of Solution

The cell needs water to for various metabolic activities. In this reaction, some water is produced by oxidation of glucose molecule. In the biosphere water is so abundant so, the amount of water which is produced during this reaction is no more than a drop in the ocean.

Hence, the statement is incorrect.

E.

Summary Introduction

To explain: In cells, the reaction consisting of oxidation of sugar molecules takes place in more than one step.

Introduction: In cellular respiration, with the help of oxygen, cells break down the glucose molecule into simpler forms. From the oxidation of glucose water, carbon dioxide is exhaled with some chemical energy in the form of ATP and small amount of heat. The general reaction is ${\text{C}}_6{\text{H}}_{12}{\text{O}}_6\text{(glucose)}\text{+}{\text{6O}}_2\to {\text{6CO}}_2\text{ +}{\text{6H}}_2\text{O}\text{+}\text{energy}$.

Answer to Problem 8Q

Correct answer: Statement is correct.

Explanation of Solution

In the cell, this reaction occurs in various steps, and from each step energy is released. If it occurs in one step, all the energy would be released in one step and it would be impossible to tackle it methodically or to drive other reactions like ATP synthesis.

Hence, the statement is correct.

F.

Summary Introduction

To explain: Many steps in the oxidation of sugar molecules involve in the reaction with oxygen gas.

Introduction: In cellular respiration, with the help of oxygen, cells break down the glucose molecule into simpler forms. From the oxidation of glucose water, carbon dioxide is exhaled with some chemical energy in the form of ATP and small amount of heat. The general reaction is ${\text{C}}_6{\text{H}}_{12}{\text{O}}_6\text{(glucose)}\text{+}{\text{6O}}_2\to {\text{6CO}}_2\text{ +}{\text{6H}}_2\text{O}\text{+}\text{energy}$.

Answer to Problem 8Q

Correct answer: Statement is incorrect.

Explanation of Solution

Oxidation of sugar molecules are step wise reaction. The molecular oxygen is only used in the very last step of in this reaction.

Hence, the statement is incorrect.

G.

Summary Introduction

To explain: Some organisms carry out the reverse reaction for oxidation of sugar molecules.

Introduction: In cellular respiration, with the help of oxygen, cells break down the glucose molecule into simpler forms. From the oxidation of glucose water, carbon dioxide is exhaled with some chemical energy in the form of ATP and small amount of heat. The general reaction is ${\text{C}}_6{\text{H}}_{12}{\text{O}}_6\text{(glucose)}\text{+}{\text{6O}}_2\to {\text{6CO}}_2\text{ +}{\text{6H}}_2\text{O}\text{+}\text{energy}$.

Answer to Problem 8Q

Correct answer: Statement is correct.

Explanation of Solution

In plants water, CO₂ in the presence of light energy converted to glucose in photosynthesis. In this process oxygen (O₂) is produced and released to the atmosphere.

Hence, the statement is correct.

H.

Summary Introduction

To explain: Some cells that grow in the absence of O₂ produce CO₂.

Introduction: In cellular respiration, with the help of oxygen, cells break down the glucose molecule into simpler forms. From the oxidation of glucose water, carbon dioxide is exhaled with some chemical energy in the form of ATP and small amount of heat. The general reaction is ${\text{C}}_6{\text{H}}_{12}{\text{O}}_6\text{(glucose)}\text{+}{\text{6O}}_2\to {\text{6CO}}_2\text{ +}{\text{6H}}_2\text{O}\text{+}\text{energy}$.

Answer to Problem 8Q

Correct answer: Statement is correct.

Explanation of Solution

Some cells in the absence of oxygen (O₂) oxidize sugars to pyruvate in glycolysis. In animal cells pyruvate is converted to lactate in which CO₂ is not released. During fermentation, yeast cells convert pyruvate to ethanol and CO₂ is produced.

Hence, the statement is correct.