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NCERT Solutions for Class 11 Biology Chapter 14 : Respiration in Plants

NCERT Solutions for Respiration in Plants Class 11 Biology Chapter 14 will help you to ace the unsolved problems in the Class 11 Science book prescribed by the NCERT for all the schools of CBSE. It presents the best alternative and a very interesting way to learn, which helps to enhance your abilities and help to get ready for CBSE Class 11 exams.

NCERT Solutions for Respiration in Plants Class 11 Notes for Chapter 14 are prepared by our expert faculties to help you to prepare for your exams in a better way and enhance your score. These NCERT Solutions also provide step by step solutions for the questions given in NCERT textbook as per CBSE Board guidelines and are also prepared according to the exam pattern.

In NCERT Solutions for Respiration in Plants Class 11 Biology Chapter 14, you will understand the concept of respiration in plants, glycolysis, fermentation, aerobic respiration, the respiratory balance sheet, amphibolic pathway and respiratory quotient in plants, tricarboxylic acid cycle and electron transport system (ETS) and oxidative phosphorylation.

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Access NCERT Solutions for Class 11 Biology Chapter 14 : Respiration in Plants

Page Number 238
Question 1
Differentiate between
(a) Respiration and Combustion
(b) Glycolysis and Kreb's cycle
(c) Aerobic respiration and fermentation
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(a)             
            
 Respiration Combustion
  1. It takes place in living cells only. 1. It does not take place in the living cell.
 2. It is carried out with the help of various enzymes. 2. Enzymes are not involved in this process.
  3. The oxidation of food and the liberation of energy occur in a step-wise manner. 3. The substances are oxidized spontaneously with sudden release of energy.
  4. It occurs at the body temperature of the organism. 4. Sudden release of energy generates high temperature of a fire.
 5. 60% of energy escapes as body heat and 40% of energy is packaged directly into new chemical energy (ATP). 5. Energy released in combustion is dissipated as heat and to some extent as light.

(b)
 Glycolysis  Krebs cycle
1. It is a linear pathway. 1. It is a cyclic pathway.
2. It occurs in the cell cytoplasm.2. It occurs in the mitochondrial matrix. 
 3. It occurs in both aerobic as well as anaerobic respiration.3. It occurs in aerobic respiration only.
4. Net generation of 2 and 2 ATP molecules occurs on the breakdown of one glucose molecule.4. It produces 6 , 2FADH, and 2 ATP molecules on the breakdown of two acetyl-CoA molecules generated after glycolysis of one glucose molecule.   
(c)
 
Aerobic respiration
 Fermentation
   1. Oxygen is used for deriving energy.1. Occurs in the absence of oxygen.
 2. Occurs in the cytoplasm and mitochondria.  2. Occurs in the cytoplasm.
 3. End products are carbon dioxide and water.
3. End products are ethyl alcohol and carbon dioxide.
 4. Complete oxidation of the respiratory substrate takes place. 4. Incomplete oxidation of the respiratory substrate takes place.
 5. About 36 ATP molecules are produced.5. Only 2 ATP molecules are produced.    
Question 2
What are respiratory substrates? Name the most common respiratory substrate.
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The compounds oxidised during the process of respiration are called as respiratory substrates. Carbohydrates, especially glucose, act as a respiratory substrate. Fats, proteins, and organic acids can also act as respiratory substrates depending upon the physiological condition of the body of an organism.
Question 3
Give the schematic representation of Glycolysis
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Glycolysis - 
(i) In this process, glucose undergoes partial oxidation to form two molecules of pyruvic acid. 
(ii) In plants, this glucose is derived from sucrose which converted into glucose and fructose by the enzyme, invertase and these two monosaccharides readily enter the glycolytic pathway. 
(iii) Glucose and fructose are phosphorylated to give rise to glucose-6-phosphate by the activity of the enzyme hexokinase. 
(iv) This phosphorylated form of glucose then isomerises to produce fructose-6-phosphate. 
(v) A chain of ten reactions, under the control of different enzymes, takes place to produce pyruvate from glucose. 
(vi) Utilization of ATP during glycolysis 
          (a)During the conversion of glucose into glucose-6-phosphate. 
          (b) During the conversion of fructose-6-phosphate to fructose-1, 6-diphosphate.     
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Question 4
What are the main steps in aerobic respiration? Where does it take place?
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The major steps in aerobic respiration and the sites where they occur are listed in the given table :

 Step Site of occurrence
 Glycolysis Cytoplasm
 Kreb's cycle Matrix of mitochondria
 Electron transport system Inner mitochondrial membrane
 Oxidative phosphorylation F0 - F1 particles in the inner mitochondrial membrane
Question 6
Explain ETS?
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Explanation:
  • ETS or electron transport system is located in the inner mitochondrial membrane. It helps in releasing and utilizing the energy stored in NADH and FADH
  • NADH which is formed during glycolysis and the citric acid cycle gets oxidized by an NADH dehydrogenase (complex I). The electrons so generated get transferred to ubiquinone through FMN. 
  • In a similar manner, FADH (complex II) generated during the citric acid cycle gets transferred to ubiquinone. The electrons from ubiquinone are received by cytochrome bc1 (complex III) and further get transferred to cytochrome c. 
  • The cytochrome c acts as a mobile carrier between complex III and cytochrome c oxidase complex, containing cytochrome a and a, along with copper centres (complex IV).
  • During the transfer of electrons from each complex, the process is accompanied by the production of ATP from ADP and inorganic phosphate by the action ATP synthase (complex V). 
  • The amount of ATP produced depends on the molecule, which has been oxidized. 3 ATP molecules are produced by the oxidation of one molecule of NADH. One molecule of FADH, on oxidation, gives 2 ATP molecules.

Electron Transport System

Question 7
Distinguish between the following.
(a) Aerobic respiration and Anaerobic respiration
(b) Glycolysis and Fermentation
(c) Glycolysis and Citric acid cycle
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(a)
 Aerobic Respiration Anaerobic Respiration
 1. Aerobic respiration takes place in the presence of free oxygen. 1. Anaerobic respiration takes place in the absence of free oxygen.
2. The first step of this process (glycolysis) takes place in the cytoplasm while the second step (Krebs cycle) is carried out in mitochondria.  2.The complete process is carried out outside the mitochondria i.e., in the cytoplasm.
 3. Glucose is completely oxidized into carbon dioxide and water. 3. Glucose is incompletely oxidized into carbon dioxide and ethyl alcohol.
 4. 38 molecules of ATP are produced by the complete oxidation of one gram-mole of glucose. 4. Only 2 molecules of ATP are formed in this process.
(b) 
Glycolysis
 Fermentation
 1. Glycolysis is a common process during aerobic and anaerobic respiration. 1. Fermentation is a type of anaerobic respiration.
 2. Pyruvic acid is produced as its end product. 2. Ethanol or lactic acid is produced as its end product.
(c)

 Glycolysis Citric acid cycle (Krebs cycle)
 1. It is a linear pathway. 1. It is a cyclic pathway.
 2. It occurs in the cell cytoplasm. 2. It occurs in the mitochondrial matrix.
 3. It occurs in both aerobic as well as in anaerobic respiration. 3. It occurs in aerobic respiration only.
 4. One glucose molecule breaks down to generate 2 NADH22 and 2 ATP molecules. 4. It produces 6 NADH22, 2 FADH22, and 2 ATP molecules on the breakdown of two acetyl-CoA molecules generated after glycolysis.
Question 8
What are the assumptions made during the calculation of net gain of ATP?
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For theoretical calculation of ATP molecules, various assumptions are made, which are as follows :
(a) It is assumed that various parts of aerobic respiration such as glycolysis, TCA cycle, and ETS occur in a sequential and orderly pathway.
(b) NADH produced during the process of glycolysis enters into mitochondria to undergo oxidative phosphorylation.
(c) A glucose molecule is assumed to be the only substrate while it is assumed that no other molecule enters the pathway at intermediate stages.
(d) The intermediates produced during respiration are not utilized in any other process.
Question 9
Discuss "The respiratory pathway is an amphibolic pathway".
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Explanation:
  • When a process involves both anabolism and catabolism then the process is known as an amphibolic pathway. 
  • In respiration, various complex molecules like carbohydrates, fatty acids, proteins are broken down into simpler molecules, this is catabolism
  • On the other hand, during the formation of fatty acids, acetyl CoA is withdrawn from the respiratory pathway. 
  • Likewise, amino acids also are withdrawn to produce proteins, this being anabolism
Question 10
Define RQ. What is RQ value for fats?
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Respiratory Quotient ( R. Q) is the ratio of the volume of carbon dioxide release to the volume of oxygen taken in respiration in the given period of time at standard temperature and pressure.
RQof fats- When fats are respiratory substrates, during germination of seeds, the fats are hydrolysed to fatty acids and glycerol. The complete oxidation of glycerol results in the RQ of 0.86. The fatty acids, being poorer in oxygen, require more O2 for complete oxidation as compared to CO2. Therefore, O2 absorption is more and CO2 liberation and RQ becomes less than unity. For example-
   RQ is 0.7 during oxidative breakdown of glycerol palmitate-
   
    RQ= Vol. of CO2\ Vol.of O= 102\145= 0.7
    The RQ of fats is mostly less than 1.
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NCERT Solutions for Class 11 Biology Chapter 14 : Respiration in Plants

NCERT Solutions for Class 11 Biology Chapter 14 Respiration in Plants  – Brief Overview

14.1 – Do Plants Breathe? In this, you will study about respiration in plants, types of respiration, respiratory quotient. 14.2 – Glycolysis In this, you will study about glycolysis which is the partial oxidation of glucose or similar hexose sugar into two molecules of pyruvic acid through a series of enzyme-mediated reaction releasing some ATP and NADH2. 14.3 – Fermentation In this, you will study about fermentation by yeast, in which pyruvic acid is converted to ethanol and CO2. 14.4 – Aerobic Respiration In this, you will study about aerobic respiration in which oxidation of glucose is done to produce energy. 14.4.1 – Tricarboxylic Acid Cycle In this, you will study about tricarboxylic acid cycle or Kreb’s cycle, terminal oxidation. 14.4.2 – Electron Transport System (ETS) and Oxidative Phosphorylation In this, you will study about electron transport system which is a metabolic pathway through which the electron passes from one carrier to another inside the inner mitochondrial membrane,  oxidative phosphorylation in which energy of oxidation-reduction is used for the production of proton gradient required for phosphorylation. 14.5 – The Respiratory Balance Sheet In this, you will calculate the ATP molecule release on oxidation of glucose. 14.6 – Amphibolic Pathway In this you will study about the amphibolic pathway includes breaking down process within a living organism is called catabolism and synthesis process is called anabolism process. 14.7 – Respiratory Quotient In this, you will study respiratory quotient which is the ratio of the volume of carbon dioxide produced to the volume of oxygen consumed in respiration over a period of time.

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Frequently Asked Questions on NCERT Class 11 Biology Chapter 14 : Respiration in Plants

Q1. Why refer to Class 11 Biology NCERT Solutions Chapter 14 Respiration in Plants?

Answer: Students should refer to the Class 11 Biology NCERT Solutions Chapter 14 to prepare for their exams. The Solutions provide answers to all the questions from the Respiration in Plants Class 11 Notes Biology NCERT textbook in simple language. Hence, students can easily understand the concepts and learn the format of answers to be written in the exam. In NCERT Solutions for Class 11 Biology Chapter 14, you will learn about cellular respiration or the mechanism of breakdown of food materials within the plant cell to release energy, and the trapping of this energy for the synthesis of ATP, various processes within the plant body.

Q2. What concepts can I learn from the NCERT Solutions for Class 11 Biology Chapter 14?

Answer:

  • 14.1 – Do Plants Breathe?
  • 14.2 – Glycolysis
  • 14.3 – Fermentation
  • 14.4 – Aerobic Respiration
  • 14.5 – The Respiratory Balance Sheet
  • 14.6 – Amphibolic Pathway
  • 14.7 – Respiratory Quotient

Q3. What are the uses of referring to the NCERT Solutions for Class 11 Biology Chapter 13?

Answer:  1. All the textbook questions are answered in a descriptive manner. 2. Students will be able to solve complex questions effortlessly using the solutions PDF. 3. By regular practice, students can jot down their areas of weakness and work on them for a better score. 4. Diagrams are present under each concept to help students learn them easily.