Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store

NCERT Solutions for Biology Class 11 Chapter 14- Breathing and Exchange of Gases

ffImage
widget title icon
Latest Updates

widget icon
Enrol Now :
NEET Test Series
widget icon
Grab Your Seat :
NEET Pro Course
widget icon
Register Today :
NEET One to One Coaching

Biology Chapter 14 Breathing and Exchange of Gases Class 11 - FREE PDF Download

NCERT Solutions for Class 11 Chapter 14 Breathing and Exchange of Gases are now available on Vedantu. This chapter includes topics such as the Human respiratory system, mechanism of breathing, exchange and transport of gases, etc.

toc-symbol
Table of Content
1. Biology Chapter 14 Breathing and Exchange of Gases Class 11 - FREE PDF Download
2. Glance on Class 11 Biology Chapter 14 Breathing and Exchange of Gases
3. Access NCERT Solutions for Biology Chapter 14 Class 11 Breathing and Exchange of Gases
4. NCERT Solutions Class 11 Biology Chapter 14: Quick Overview of Topics Covered
5. Benefits of Solutions for Chapter 14: Breathing and Exchange of Gases Class 11 NCERT
6. Study Materials for Chapter 14 Breathing and Exchange of Gases Class 11
7. NCERT Solutions for Class 11 Biology FREE PDF | Other Chapter-wise Links
8. Related Important Links for CBSE Class 11 Biology NCERT Solutions
FAQs


Class 11 Biology chapter Living World NCERT solutions are prepared by our subject experts with close reference to the latest edition of the NCERT textbook. All the important topics and sub-topics are covered according to the latest CBSE Class 11 Biology Syllabus. Therefore, students can rely on these NCERT solutions for their exam preparation.


Glance on Class 11 Biology Chapter 14 Breathing and Exchange of Gases

  • Master the fundamentals and unlock a comprehensive understanding of breathing and exchange of gases NCERT solutions for class 11 biology chapter 14.

  • Concise explanations for all the questions in the class 11 biology chapter 14 exercise.

  • Complex topics like the Introduction to the process of respiration, which involves breathing (ventilation) and the exchange of gases (oxygen and carbon dioxide) between the body and the environment, are explained easily.

  • Vedantu has introduced Biology Class 11 PDF for Breathing and Exchange of Gases NCERT gives the  Description of the process of gas exchange, pulmonary circulation, and carbon dioxide diffuses from the blood into the alveoli to be exhaled.

  • Chapter 14 Class 11 Breathing and Exchange of Gases falls under the 5th unit named Human Physiology and explains the mechanism of transportation of gases.

  • Chapter 14 Breathing and Exchange of Gases Class 11 NCERT deals with differentiation, meaning, importance, and definitions of breathing and respiration in an in-depth manner. 

  • These NCERT Solutions provide answers to the topics dealing with the human respiratory system, the organs of the human respiratory system, the gases exchanged while breathing and respiration take place, disorders of the human respiratory system, and many other concepts.

Competitive Exams after 12th Science
tp-imag
bottom-arrow
tp-imag
bottom-arrow
tp-imag
bottom-arrow
tp-imag
bottom-arrow
tp-imag
bottom-arrow
tp-imag
bottom-arrow

Access NCERT Solutions for Biology Chapter 14 Class 11 Breathing and Exchange of Gases

1. Define vital capacity. What is its significance?  

Ans. The vital capacity (Vc) is the maximum amount of air that a person can expel from the lungs after a maximum inspiration. The quantity of cubic inches or cubic centimetres of air that can be forcefully expelled following a full inhalation is the lungs' breathing capacity. In the human body, it is around 3.5 to 4.5 litres. 

Promotes the supply of fresh air and the removal of stale air, thus increasing the gas exchange between tissue and the environment.


2. State the volume of air remaining in the lungs after a normal breathing. 

Ans. The volume of air remaining within the lungs after a traditional expiration is understood as functional residual capacity (FRC). It comprises expiratory reserve volume (ERV) and residual volume (RV). ERV is the maximum volume of air that will be exhaled after a traditional expiration. It's about 1000 ml to 1500 ml. RV is the volume of air remaining within the lungs after maximum expiration. It's about 1100 mL to 1500 ml.

∴ FRC=  ERV + RV  ≅1500 + 1500 = 3000 mL  

The functional residual capacity of the human lungs is about 2500 – 3000 ml. 


3. Diffusion of gases occurs in the alveolar region only and not in the other parts of the respiratory system. Why?  

  • Ans. Each alveolus is composed of a thin, highly permeable layer of squamous cells. Blood capillaries are also composed of layers of squamous cells. The oxygen-rich air enters the human body through the nose and reaches the alveoli. 

  • The deoxygenated blood from the body is transported to the heart through a vein. The heart pumps it into the lungs to supply oxygen. 

  • The exchange of O2 and CO2 occurs between the capillaries surrounding the alveoli and the gas present in the alveoli. Therefore, the alveoli are the place for gas exchange. Due to pressure or concentration differences, gas exchange is carried out by simple diffusion.

  • The barrier between the alveoli and, by extension, the capillaries is extremely thin, allowing gases to diffuse from higher partial pressures to lower partial pressures. The blood that reaches the alveoli has the lower partial pressure of O2 and better partial pressure of CO2   as compared to alveolar air. Hence, oxygen gas diffuses into the blood. Simultaneously, CO2 diffuses out of the blood and into the alveoli.


4. What are the major transport mechanisms for CO2? Explain.  

Ans. Plasma and red blood cells carry carbon dioxide because they are easily soluble in water.

Through plasma:  

Approximately 7% of the CO2 is transported through the plasma in a dissolved state. Carbon dioxide will combine with the water to form carbonic acid.  

As the process of forming carbonic acid is slow, only a small amount of carbon dioxide is carried this way.  

Through RBCs:  

Approx 25% of CO 2 is transported with the help of red blood cells as carbaminohemoglobin.  Carbon dioxide will bind to the amino groups on the polypeptide chains of haemoglobin and form a compound which is known as carbaminohemoglobin.  

Through sodium bicarbonate:  

Approximately 70% of CO2 is transported within the sort of sodium bicarbonate. As CO2 diffuses into the plasma, an outsized amount of it combines with water to make acid within the presence of the enzyme carbonic anhydrase. Carbonic anhydrase is an enzyme that contains zinc that accelerates the formation of acid. This carbonic acid formed will dissociate into bicarbonate (HCO3–) and hydrogen ions (H+). 

Carbonic anhydrase CO H O 2 2 + ⎯⎯⎯⎯⎯⎯→H CO 2 3 

Carbonic H CO HCO H 2 3 anhydrase 3 ⎯⎯⎯⎯→ +− +


5. What will be the pO2and 2 pCO in the atmospheric air compared to those in the alveolar air? 

(i) pO2lesser, 2 pCOhigher  

(ii) pO2higher, 2 pCOlesser  

(iii) pO2higher, 2 pCOhigher  

(iv) pO2lesser, 2 pCOlesser 

Ans. (ii) pO2 higher, 2 pCO lesser  

The partial pressure of oxygen in atmospheric air tends to be more than the partial pressure of oxygen in alveolar air. In atmospheric air, the pO2 is approximately 159 mm Hg. In alveolar air, it's approximately 104 mm Hg. The partial pressure of CO2 in atmospheric air is lower. as CO2 within the alveolar air. In atmospheric air, the pCO2 is around 0.3 mmHg. In alveolar air, it's about 40 mm Hg.


6. Explain the process of inspiration under normal conditions. 

  • Ans. Inspiration, or inhalation, is the process by which air is brought into the lungs from outside the body. It's performed by creating a pressure gradient between the lungs and therefore the atmosphere. 

  • When air enters the lungs, the diaphragm expands into the abdomen, increasing the space within the thoracic cavity to accommodate the air that's inhaled.

  • The volume of the chest chamber within the anteroposterior axis increases because the external intercostal muscles contract, causing the ribs and sternum to maneuver outward, increasing the quantity of the chest chamber within the dorsoventral axis. Chest volume results in an identical increase in lung volume. As a result of this increase, the intrapulmonary pressure becomes less than air pressure, causing air from outside the body to flow into the lungs.


Inspiration and Expiration Reworked

Inspiration and Expiration Reworked


7. How is respiration regulated?  

Ans. The center of the breathing rhythm, located in the area of ​​the medulla of the brain, is primarily responsible for regulating breathing. The pneumatic center can change the function of the respiratory rhythm center by sending signals to reduce the inspiratory rate. The chemosensitive region is near the respiratory center. It is sensitive to carbon dioxide and hydrogen ions. This area sends signals to change the expiratory rate to remove connections.


Receptors in the carotid artery and aorta record the concentrations of carbon dioxide and hydrogen ions in the blood. As the carbon dioxide level rises, the respiratory center sends nerve impulses for the necessary changes. 


8. What is the effect of 2 pCO on oxygen transport? 

Ans. pCO2 plays a really important role in oxygen transport. within the alveolus, low pCO2 and high pO2 promote the formation of haemoglobin. In tissues, high pCO2 and low pO2 favour the dissociation of an oxygen atom from the oxyhemoglobin. Hence the affinity of haemoglobin for oxygen is aggravated by the decrease in pCO2 within the blood. Therefore, oxygen is carried within the blood as oxyhemoglobin, and oxygen is dissociated from it within the tissues.


9. What happens to the respiratory process in a man going up a hill?  

Ans. The oxygen content of the atmosphere decreases with an increase in altitude. As a result, each breath a man takes upward provides him with less oxygen. The amount of oxygen in the blood reduces as a result. The respiratory rate increases in response to a lack of oxygen. the oxygen content of the blood. At the same time, the frequency of the heartbeat increases in order to increase the oxygen supply to the blood.


10. What is the site of gaseous exchange in an insect?  

Ans. In the case of insects, the exchange of gas takes place through a huge network of tubes known collectively because of the tracheal system. The tiny openings which are present on the edges of an insect's body are called stigmas. Oxygen-rich air enters through the spiracles. The spiracles are connected to the network of the tubes. Oxygen enters into the windpipe from the spiracles. From here, oxygen diffuses into the body cells. The movement of CO2 follows the other path. CO2 from the body's cells first enters the windpipe then leaves the body through the spiracles.


11. Define the oxygen dissociation curve. Can you suggest any reason for its sigmoidal pattern? 

Ans. The oxygen dissociation curve is a graph showing the percentage saturation of oxyhemoglobin at various partial pressures of oxygen.


Oxygen Dissociation Curve

Oxygen Dissociation Curve


  • The curve shows us the equilibrium of oxyhemoglobin and hemoglobin at different partial pressures. 

  • The partial pressure of oxygen in the lungs is high, so hemoglobin binds to oxygen and forms oxyhemoglobin. 

  • Tissues have low levels of oxygen, so oxyhemoglobin releases oxygen in tissues to form hemoglobin. 

  • The sigmoid form of the dissociation curve is due to the binding of oxygen to hemoglobin. As the first oxygen molecule binds to hemoglobin, the binding affinity of the second oxygen molecule increases. The hemoglobin then attracts more oxygen.


12. Have you heard about hypoxia? Try to gather information about it, and discuss it with your friends.  

Ans. Hypoxia is a condition characterized by insufficient or decreased oxygen supply to the lungs and caused by various extrinsic factors such as decreased pO2, insufficient oxygen, etc. The different types of hypoxia are;-.

  • Hypoxemic hypoxia  

In this hypoxia, there is a decrease in the oxygen content of the blood due to the low oxygen partial pressure in the arterial blood.  

  • Anaemic hypoxia  

This hypoxia results in a decrease in haemoglobin concentration.

  • Stagnant or ischemic hypoxia  

This type of hypoxia results in a lack of oxygen in the blood due to poor circulation. It occurs when a person is exposed to a cold temperature for a long period of time.  

  • Histotoxic hypoxia 

In this type of hypoxia, the tissues cannot use oxygen, which occurs with carbon monoxide or cyanide poisoning.


Common symptoms of hypoxia include:


  • Shortness of breath

  • Rapid breathing

  • Rapid heart rate

  • Lethargy

  • Confusion

  • Anxiousness

  • Slurred speech


13. Distinguish Between  

(a) IRV and ERV  

Inspiratory Reserve Volume (IRV)

Expiratory Reserve Volume(ERV)

This is defined as the maximum volume of the air that can be breathed in after a normal inspiration.

It is the maximum volume of air that can be exhaled i.e released out after a normal expiration.

It is approx 2500-3500 ml in human lungs.

It is approx 1000-1100 ml in human lungs. 


(b) Inspiratory Capacity and Expiratory Capacity  

Inspiratory Capacity (IC)

Expiratory Capacity (EC)

It is defined as the volume of the air that can be inhaled easily after a normal expiration.

It is defined as the volume of air that can be exhaled easily after a normal inspiration.

It comprises inspiratory reserve volume and tidal volume.

IC = TV + IRV

It comprises expiratory reverse volume and tidal volume.

EC = TV + ERV


(c) Vital Capacity and Total lung Capacity 

Vital Capacity (VC) 

Total lung Capacity (TLC)

It is defined as the maximum volume of air that can be exhaled easily after a maximum inspiration. It includes IC and ERV.

It is defined as the volume of air in the lungs after maximum inspiration. It includes IC, ERV, and residual volume.


It is approximately 4000 mL in the human lungs.

It is approximately 5000 – 6000 mL in the human lungs.


14. What is Tidal volume? Find out the Tidal volume (approximate value) for a healthy human in an hour. 

Ans. Tidal volume is defined as the volume of air that is inspired or expired during normal respiration.  It is approximately 6000 to 8000 mL of air per minute.  

The hourly tidal volume for a human with a good health is calculated as shown below:  

Tidal volume = 6000 to 8000 mL/minute  

Tidal volume in an hour = 6000 to 8000 mL ×(60 min)  

= 3.6 x10 5 ml to 4.8x10 5 ml

Therefore, the hourly tidal volume for a human with good health is around

3.6 x10 5 ml to 4.8x10 5 ml.


NCERT Solutions Class 11 Biology Chapter 14: Quick Overview of Topics Covered

List of Subtopics Covered in Chapter 14: Breathing and Exchange of Gases

Topics

Subtopics

Respiratory Organs

Human Respiratory System

Mechanism of Breathing

Respiratory Volumes and Capacities

Exchange of Gases

-

Transport of Gases

Transport of Oxygen, Transport of Carbon dioxide

Regulation of Respiration 

-

Disorders of the Respiratory System

-


Benefits of Solutions for Chapter 14: Breathing and Exchange of Gases Class 11 NCERT

  • As the solutions are written and explained by Biology experts, the concepts are easily understandable by students.

  • The solutions are written by taking into consideration the pattern and marks allotted to the chapter.

  • Chapter 14 Breathing and Exchange of Gases Class 11 NCERT deals with differentiation, meaning, importance, and definitions of breathing and respiration in an in-depth manner. 

  • Overview of common respiratory disorders such as asthma, chronic obstructive pulmonary disease (COPD), pneumonia, and tuberculosis, their causes, symptoms, and treatment are the important topics from the exam point of view.

  • All the textbook questions like the mechanism of transportation of gases with detailed examinations and diagrams are drawn where the need arises.

  • CBSE guidelines are followed while preparing the answers, making the structure more accurate and systematic.

  • Breathing and Exchange of Gases questions and answers PDF could be used for a quick revision before the examinations as all the answers will be available in the same place.


Study Materials for Chapter 14 Breathing and Exchange of Gases Class 11


Conclusion

Students must read the solutions for Chapter 14 Breathing and Exchange of Gases NCERT while preparing for their Class 11 CBSE exam. It is also essential for the NEET Exam. This article covers all the critical concepts and provides breathing and exchange of gases questions and answers PDF. The solutions are presented in simple language, since they were chosen by Subject Experts.


NCERT Solutions for Class 11 Biology FREE PDF | Other Chapter-wise Links

Given below are the other chapter-wise Links for the Solutions for Biology NCERT Class 11.



Related Important Links for CBSE Class 11 Biology NCERT Solutions

FAQs on NCERT Solutions for Biology Class 11 Chapter 14- Breathing and Exchange of Gases

1. Explain the Effects on the Respiratory System of a Man While Climbing a Hill.

The amount of oxygen keeps on decreasing as the altitude increases. The amount of oxygen starts decreasing as the man starts climbing up the hill. As the level of oxygen starts decreasing, the man is unable to breathe in the required amount of oxygen into the blood. In response to the declined oxygen in the blood, the respiratory rate increases, making it difficult to breathe. The blood is in a constant need for more oxygen. To supply the blood with oxygen, the heartbeat rate of that person also increases. To learn the concepts related to respiration, students can refer to solutions provided by Vedantu for Class 11 breathing and exchange of gases.

2. According to Chapter 14 Breathing and Exchange of Gases NCERT, Diffusion of gases occurs in the alveolar region only and not in the other parts of the respiratory system. Why?

For efficient diffusion of gases, the region should meet the following characteristics to be capable enough for the important process. They are;

  • The membrane should be permeable to gases and should be thin and moist too.

  • It should have a large surface area.

  • It should have high vascularity.

All these characteristics are met by the alveolar membrane, thus, it is the best place for respiratory exchange among all other parts of the respiratory system. A detailed explanation is available on Vedantu.

3. What happens to the respiratory process in a man going up a hill according to Chapter 14 Breathing and Exchange of Gases Class 11 NCERT?

With increasing altitude, the oxygen level depreciates in the atmosphere. Therefore, when a man climbs up the hill, the amount of oxygen he gets while breathing also decreases. Thus, oxygen levels in the blood also decrease and as a result of this, to compensate for this declining level of oxygen, the respiratory rate increases. The heart also has to work faster to supply oxygen to the organs and thus, heartbeat increases. These solutions make it easier for students by offering detailed answers to all textbook questions. Furthermore, all the textual responses are created by top Biology teachers who have worked hard to ensure that students fully comprehend each idea.

4. Explain the process of inspiration under normal conditions as discussed in Chapter 14 Breathing and Exchange of Gases NCERT PDF.

The process through which fresh air enters the lungs is known as inspiration. The diaphragm, intercostal muscles, and abdominal muscles are all crucial. The most significant muscles for inspiration are the diaphragm and external intercostal muscles. The diaphragm and external intercostal muscles contract, increasing the volume of the thoracic cavity. Relaxation of abdominal muscles occurs during inspiration, allowing the diaphragm to compress the abdominal organs. As a result, the overall volume of the thoracic cavity grows, and the air pressure in the lungs decreases. Because of the increased pressure outside the body, the air is now rushing into the lungs. This is the order in which air flows during inspiration.

5. How is respiration regulated according to Class 11 Biology Chapter 14 Breathing and Exchange of Gases?

Both the neurological and chemical systems are in charge of respiration. The medulla oblongata and pons Varolii include clusters of neurons that make up the respiratory centre in the brain. The respiratory centre is in charge of controlling the rate and depth of breathing.


The dorsal respiratory group of neurons is found in the medulla oblongata's dorsal part. This group of neurons is mostly in charge of inspiration.


In the ventrolateral region of the medulla oblongata, there is a group of neurons known as the ventral group. These can either inspire or cause exhalation.


Chemoreceptors in the carotid and aortic bodies chemically control respiration. Excess carbon dioxide or hydrogen ions stimulate the respiratory centre of the brain, which increases the inspiratory and expiratory impulses to the respiratory muscles. Acidosis is caused by increased CO2. The importance of oxygen in respiratory rhythm regulation is negligible. For more, refer to the notes of Chapter 14 of Class 11 Biology by Vedantu which are available to download free of cost.

6. Define the oxygen dissociation curve according to Biology Chapter 14 Breathing and Exchange of Gases Class 11. Can you suggest any reason for its sigmoidal pattern?

A curve called the oxygen haemoglobin dissociation curve graphically depicts the relationship between partial pressure of oxygen (pO2) and % saturation of haemoglobin with oxygen (O2) (also called oxygen dissociation curve).


The sigmoidal structure of the oxygen haemoglobin dissociation curve is due to two features that are important in oxygen transport. These are the two properties:

  • Despite considerable increases in oxygen tension beyond p02 of 70-80 mm Hg, minimal oxygen loss from haemoglobin occurs. The comparatively flat segment of the curve depicts this.

  • Any additional drop in p02 below 40 mm Hg results in a disproportionately higher oxygen release from the haemoglobin. It causes the curve to be sigmoid and results in the steeper portion of the curve.

7. What increases gas exchange in the lungs, as explained in Breathing and Exchange of Gases NCERT?

Here are some reasons for increasing gas exchange in the lungs:

  • Deep breathing

  • Larger surface area

  • Increased Alveolar Oxygen Pressure

  • Decreased alveolar CO2

  • Increase blood flow

  • Hemoglobin concentration

8. What is responsible for breathing and gas exchange?

It is a process of well-coordinated interplay between several systems, such as:

  • The Respiratory System ( which provides the passage of air)

  • Neuromuscular System (controls the mechanics of breathing)

  • Circulatory System (transport system for the exchanged gases)

Students can refer to and download Chapter 14 breathing and Exchange of gases NCERT solutions available on Vedantu’s website to learn the concepts and clear their doubts.

9. What are the characteristics of gas exchange?

The characteristics of gas exchange explained in Class 11 breathing and exchange of gases are as follows:

  • Larger surface area

  • Diffusion

  • Passive process

  • Concentration gradient

  • Matching ventilation and perfusion

10. Which part of the body controls breathing?

The part of the body that controls breathing is the brainstem, specifically a region called the medulla oblongata, which sends signals to the muscles. Students can refer to answers provided by Vedantu and also get insights on breathing and exchange of gases questions and answers PDF for FREE.