NCERT Exemplar Class 11 Biology Solutions Chapter 17 Breathing and Exchange of Gases
The NCERT Exemplar Class 11 Biology Solutions Chapter 17 Breathing and Exchange of Gases provides a simple explanation of how living beings absorb oxygen and eliminate carbon dioxide. This chapter discusses important issues like the human respiratory system and respiratory volumes. By practising the MCQs given in these solutions, students can improve their knowledge of fundamental concepts and prepare well for exams. The NCERT exemplar solutions include a vast collection of objective questions and solutions, which help the students relate what they study to the real world.
This Story also Contains
- Detailed Answers to the NCERT Exemplar Class 11 Biology Chapter 17 Solutions MCQs
- Access Answers to NCERT Exemplar Class 11 Biology Chapter 17 Solutions- Very Short Answer Type Questions:
- Get Answers to NCERT Exemplar Class 11 Biology Chapter 17 Solutions- Short Answers Type Questions:
- Know Answers to NCERT Exemplar Class 11 Biology Chapter 17 Solutions- Long Answer Type Question:
- Major Topics and Subtopics in NCERT Exemplar Class 11 Biology Chapter 17
- Approach to solve Class 11 Biology Chapter 17 questions
- Important Question from NCERT Exemplar Class 11 Biology Chapter 17
- NCERT Exemplar Class 11 Biology Solutions Chapter-Wise
Respiration, or breathing, varies between living things since they have different respiratory organs. These sample solutions make the students aware of these variations and provide them with more confidence while answering the NCERT Class 11 Biology Book problems. These questions improve not only performance on exams but also a strong base in the subject of respiration if practised regularly.
Detailed Answers to the NCERT Exemplar Class 11 Biology Chapter 17 Solutions MCQs
Different forms of questions, like MCQs, short answers, and long answers with the required diagrams, are provided below. Practising these will help you understand the pattern and these concepts easily and effectively.
Question:1
Answer:
The answer is option (d) Tracheal tubes exchange O2 /CO2 directly with the haemocoel which then exchanges with tissues.Explanation: - The process of respiration occurs directly because there exists no other medium for the transmission of air; instead, the cells exchange oxygen and carbon dioxide with the air in the tubes.
Question:2
Regarding the functions of our respiratory system, mark the wrong entry.
a. Humidifies the air
b. Warms up the air
c. Exchange of gases
d. Cleans up the air
Answer:
The answer is option (d) cleans up the air because all other functions are performed by the respiratory system.
Question:3
Answer:
The answer is the option (d) Cessation of breathing
The process of breathing includes the diffusion of gases. A person with a chest cavity caused due to an accident without any damage is the cessation of breathing. This might be due to inflation or deflation of the air-tight chest cavity.
Question:4
Answer:
The answer is option (b) It reduces O2 transportExplanation: - Exposure to carbon monoxide is harmful to animals because it leads to the transport of less oxygen. Carbon monoxide binds with the haemoglobin of the blood, thus leaving oxygen behind. The cells, not being able to respire thus and cannot live for a long time.
Question:5
Mark the true statement among the following concerning normal breathing.
(a) Inspiration is a passive process whereas expiration is active
(b) Inspiration is an active process whereas expiration is passive
(c) Inspiration and expiration are active processes
(d) Inspiration and expiration are passive process
Answer:
The answer is option (b) Inspiration is an active process, whereas expiration is passive.Explanation: - Inspiration is an active process, but expiration is passive. Inspiration occurs because the diaphragm muscles contract to increase the volume of the thoracic cavity, but expiration leads to relaxation of the diaphragm muscles.
Question:6
Answer:
The answer is the option (c) Vital Capacity.Question:7
Mark the incorrect statement in context to O2 binding to Hb.
(a) Lower pH
(b) Lower temperature
(c) Lower pCO2
(d) Higher pO2
Answer:
The answer is the option (a) Lower pHExplanation: - Vital Capacity is the amount of air that a person forcefully breathes in. The binding of oxygen with haemoglobin is related to the partial pressure exhibited by O2. In the alveoli, higher partial pressure of O2, lower partial pressure of CO2, and less H+ concentration facilitate the formation of oxyhaemoglobin.
Question:8
Answer:
The answer is the option (d) Diaphragm and intercostal musclesExplanation: The diaphragm and intercostal muscles are involved in the normal breathing process in humans.
Question:9
Incidence of Emphysema- a respiratory disorder is high in cigarette smokers. In such cases
(a) The bronchioles are found damaged
(b) The alveolar walls are found damaged
(c) The plasma membrane is found damaged
(d) The respiratory muscles are found damaged
Answer:
The answer is the option (b).Explanation: - The alveolar walls are damaged in the patients of high cigarette smokers.
Question:10
(a) Medullary inspiratory centre
(b) Pneumotaxic centre
(c) Apneustic centre
(d) Chemosensitive centre
Answer:
(b) Pneumotaxic centre is the correct answer.
Question:11
Answer:
The answer is option (b) pO2 is high and pCO2 is lowExplanation: - The partial pressure of O2 should be high and that of CO2 should be low when CO2 dissociates from carbamino-haemoglobin.
Question:12
Answer:
The answer is the option (d) SpirometerExplanation: A spirometer is used to estimate the breathing volumes.
Question:13
(a) (i) Incorrect (ii) Incorrect (iii) Incorrect (iv) correct
(b) (i) Incorrect (ii) correct (iii) Incorrect (iv) correct
(c) (i) correct (ii) correct (iii) Incorrect (iv) correct
(d) (i) correct (ii) Incorrect (iii) correct (iv) Incorrect
Answer:
The answer is the option (b) (i) Incorrect (ii) Correct (iii) Incorrect (iv) Correct.Question:14
Answer:
The answer is the option (a) High pCO2Explanation: -The curve of oxygen and haemoglobin is shifted to the right when the pO2 decreases, pCO2 increases, the concentration of H+ increases, pH decreases and body temperature increases.
Question:15
Match the following and mark the correct options
| Animal | Respiratory organ | ||
| A. | Earthworm | (i) | Moist cuticle |
| B. | Aquatic Arthropods | (ii) | Gills |
| C. | Fishes | (iii) | Lungs |
| D. | Birds/Reptiles | (iv) | Trachea |
(a) A—(ii), B—(i), C—(iv), D—(iii)
(b) A—(i), B—(iv), C—(ii), D—(iii)
(c) A—(i), B—(iii), C—(ii), D—(iv)
(d) A—(i), B—(iv), C—(ii), D—(iii)
Answer:
The answer is the option (d) A—(i), B—(iv), C—(ii), D—(iii)
Access Answers to NCERT Exemplar Class 11 Biology Chapter 17 Solutions- Very Short Answer Type Questions:
The detailed answers to the Very Short Answer questions are given below:
Question:1
Define the following terms
a. Tidal volume
b. Residual volume
c. Asthma
Answer:
(a) Tidal volume is the volume of air inspired or expired under normal breathing. A normal individual has a TV of 500 mL.(b) Residual volume is the volume of air remaining in the lungs even after a forceful expiration. A normal individual has an RV of 1100 to 1200 mL.
(c) Asthma is the difficulty in breathing due to inflammation of the bronchi or bronchioles.
Question:2
Answer:
The fluid is known as pleura. Its job is to reduce the friction on the lungs and act as a protective covering.Question:3
Name the primary site of exchange of gases in our body.
Answer:
The primary site of gas exchange in our body is known as Alveoli.Question:4
Cigarette smoking causes emphysema. Give reason.
Answer:
Emphysema is caused because of excessive smoking, leading to damage to the alveolar walls and reduction of the respiratory surface.Question:5
Answer:
5mL is the amount of O2 supplied to tissues through every 100 mL of oxygenated blood under normal physiological conditions.Question:6
Answer:
The remaining oxygen is transported through the plasma of the blood.Question:7
Answer:
TV (500 mL); RV (1100 to 1200 mL); EC (1500 to 1600 mL); IRV (2500 to 3000 mL).Question:8
Answer:
(a) Inspiratory Capacity (IC) = _TV_ +IRV(b) _EC_ = TV + ERV
(c) Functional Residual Capacity (FRC) = ERV + _RV_
Question:9
Name the organs of respiration in the following organisms:
a. Flatworm
b. Birds
c. Frog
d. Cockroach
Answer:
(a) Flatworm - body surface(b) Birds - Lungs
(c) Frog - Lungs and skin
(d) Cockroach – Trachea
Question:10
Answer:
The diaphragm and Intercostal muscles are involved in creating a pressure gradient between the lungs and the atmosphere during normal respiration.
Get Answers to NCERT Exemplar Class 11 Biology Chapter 17 Solutions- Short Answers Type Questions:
The detailed answers to the Short Answer questions are given below:
Question:1
State the different modes of C02 transport in the blood.
Answer:
The different modes of transport of carbon dioxide in the blood are as follows:- About 20 – 25% of CO2 is carried by RBCs
- About 70% of CO2 is transported as a bicarbonate
- About 7% of CO2 is carried in the dissolved state through the plasma
Question:2
Answer:
The solubility of CO2 is 20 – 25% higher as compared to O2. Because of this, the diffusion rate of CO2 via the diffusion membrane per unit difference in partial pressure is greater than the diffusion rate of O2.Question:3
Answer:
The following is the correct sequence:1. Diffusion of gases (O2 and CO2 ) across the alveolar membrane.
2. Transport of gases by blood.
3. Utilisation of O2 by the cells for catabolic reactions and resultant release of CO2.
4. Pulmonary ventilation by which atmospheric air is drawn in and CO2-rich alveolar air is released out.
5. Diffusion of O2 and CO2 between blood and tissues.
Question:4
A) Inspiratory and Expiratory Reserve Volume
B) Vital Capacity and Total Lung Capacity
C) Emphysema and occupational respiratory disorder
Answer:
A)| Inspiratory Reserve Volume | Expiratory Reserve Volume |
| The additional volume of air a person can inspire by a forcible inspiration is called inspiratory reserve volume (IRV). | The additional volume of air a person can expire by a forced expiration is called expiratory reserve volume (ERV). |
| In a normal individual, IRV is about 2500 to 3000 mL | In a normal human, ERV is about 1000 to 1100 mL. |
B)
| Vital capacity | Total Lung Capacity |
| The maximum volume of the air one can breathe after a forceful expiration, is called Vital Capacity. | The total volume of air in the lungs at the end of a forced inspiration is called Total Lung Capacity. |
C)
| Emphysema | Occupational Respiratory disorder |
| Alveoli walls are damaged in emphysema | any other part of the respiratory system is damaged in occupational respiratory disorder |
| Caused due to smoking | Caused due to fine particles generated |
Know Answers to NCERT Exemplar Class 11 Biology Chapter 17 Solutions- Long Answer Type Question:
The detailed answers to the Long Answer questions are given below:
Question:1
Explain the transport of O2 and CO2 between alveoli and tissue with a diagram.
Answer:
In alveoli, the partial pressure of O2 is 104 mm Hg, and that of CO2 is 40 mm Hg. While the blood is deoxygenated, pO2 is 40 mm Hg. This is much less than the pO2 in alveoli.
Thus oxygen enters the blood in the alveoli. In deoxygenated blood, the partial pressure of CO2 is 45 mm Hg. This is much more than the partial pressure of CO2 in alveoli. Thus, carbon dioxide exits from tissue cells and enters the alveoli.
Once the blood reaches the tissues, the partial pressure of oxygen present in the oxygenated blood is 95 mm.
Thus, oxygen from the blood enters the tissues. At the tissue level, the partial pressure of carbon dioxide in deoxygenated blood is more than that in oxygenated blood. Hence, carbon dioxide exits from the tissues.
Question:2
Explain the mechanism of breathing with neatly labelled sketches.
Answer:
The process of breathing comprises two stages: -Inspiration:
- The intercostal muscles initiate contraction of the diaphragm. This increases the volume of the thoracic chamber.
- Ribs and diaphragm are moved upwards. As a result, the pressure inside the lungs becomes less than atmospheric pressure. This difference in pressure causes air to move inside the lungs.
- The intercostal muscles and the diaphragm relax and move to their original position.
- Ribs and sternum return to their original position.
- The volume inside the thoracic chamber reduces. As a result, the pressure inside the lungs becomes more than the atmospheric pressure and the air is forced out of the lungs.
Question:3
Explain the role of the neural system in the regulation of respiration
Answer:
The Central Nervous system is important in respiration because:- The respiratory rhythm centre is present in the medulla. It is a specialised centre and is responsible for the regulation of respiration.
- The pneumatoxic centre is present in the pons of the brain. It moderates the functions of the respiratory rhythm centre. Nerve signals present in pneumotaxic centre reduce the duration of inspiration thus altering the respiratory rate.
- A chemosensitive area is also there adjacent to the rhythm centre. This is highly sensitive to CO2 and hydrogen ions. An increase in these substances can activate this centre.
- The chemosensitive area gives a signal to the rhythm centre to make adjustments to eliminate these substances. Some receptors are associated with the aortic arch and the carotid artery. They also recognise changes in CO2 and H+ concentration.
- After that, they send necessary signals to the rhythm centre so that corrective actions can be taken. The role of oxygen is quite insignificant in the regulation of the respiratory rhythm centre.
NCERT Exemplar Class 11 Solutions for Other Subjects
Major Topics and Subtopics in NCERT Exemplar Class 11 Biology Chapter 17
The topics and subtopics in Breathing and Exchange of Gases are:
1. Respiratory Organs
2. Mechanism of Breathing
3. Exchange of gases
4. Transport of gases
5. Regulation of respiration
6. Disorders of the respiratory system
Also, Read NCERT Solution subject-wise
Approach to solve Class 11 Biology Chapter 17 questions
To solve the Breathing and Exchange of Gases questions effectively, follow these simple steps:
- Understand the organisation and function of the respiratory organs and systems.
- Revise mechanisms of breathing, gas exchange, and transport in human beings.
- Practice drawing and labelling important diagrams, such as the human respiratory system.
- Solve all questions given here, with special emphasis on respiratory disorders and regulation.
- Review and summarise keywords, and clear doubts through notes and discussions.
Must Read NCERT Notes subject-wise
Important Question from NCERT Exemplar Class 11 Biology Chapter 17
Here are some extra questions along with their answers to help you practice and strengthen your understanding of the chapter Breathing and Exchange:
Respiration in insects is called direct because
a) The cells exchange O₂/CO₂ directly with the air in the tubes
b) The tissues exchange O₂/CO₂ directly with the coelomic fluid
c) The tissues exchange O₂/CO₂ directly with the air outside through the body surface
d) Tracheal tubes exchange O₂/CO₂ directly with the haemocoel, which then exchange with tissues
Answer: d) Tracheal tubes exchange O₂/CO₂ directly with the haemocoel, which then exchanges with tissues
Explanation:
Respiration in insects is called "direct" because their tracheal system delivers oxygen straight from the outside environment to the body tissues without involving the circulatory system for gas transport. Air enters through spiracles and travels via a network of tracheal tubes that branch into fine tracheoles, reaching deep into the body and often ending near or within individual cells. These tracheal tubes open into the haemocoel (the primary body cavity), allowing oxygen and carbon dioxide to be exchanged directly between the air in the tracheae and the tissues. This direct delivery system is highly efficient and bypasses the need for oxygen to be carried by blood, which is why insect respiration is termed "direct."
Also, check the NCERT Books and the NCERT Syllabus here
NCERT Exemplar Class 11 Biology Solutions Chapter-Wise
Biology chapter-wise exemplar solutions are given below:
Frequently Asked Questions (FAQs)
Q: What are the main topics covered in Chapter 17: Breathing and Exchange of Gases?
A:
The chapter addresses respiratory organs in various organisms, the human respiratory system (including nasal chamber, pharynx, larynx, trachea, bronchi, alveoli), the mechanism of breathing, respiratory volumes and capacities, exchange and transport of gases (oxygen and carbon dioxide), regulation of respiration, and disorders of the respiratory system.
Q: How does respiration in insects differ from that in humans?
A:
Insects respire through a direct system where tracheal tubes exchange gases directly with the haemocoel, which then exchanges with tissues. This is called "direct respiration" because there is no involvement of blood in gas transport, unlike in humans where gases are transported via the bloodstream.
Q: What is the significance of vital capacity in the respiratory system?
A:
Vital capacity represents the maximum amount of air a person can expel from the lungs after a maximum inhalation. It indicates the greatest amount of oxygen available for glucose oxidation, which is crucial for energy production in the body.
Q: What happens if a person suffers a puncture in the chest cavity without lung damage?
A:
A puncture in the chest cavity, even without lung damage, can lead to cessation of breathing. This is because the pressure difference required for lung inflation is lost, preventing normal breathing movements.
Q: How does oxygen transport occur in human beings?
A:
Oxygen transport in humans primarily occurs through the binding of oxygen to hemoglobin within red blood cells, which then carry the oxygenated blood from the lungs to the body tissues.
Q: What are the major differences between inspiration and expiration?
A:
Inspiration (inhaling) is an active process where the diaphragm and intercostal muscles contract, expanding the lungs and drawing air in; expiration (exhaling) is generally passive, where these muscles relax, causing the lungs to recoil and air to be expelled.
Q: How is carbon dioxide transported in the blood?
A:
Carbon dioxide is transported in the blood primarily as bicarbonate ions (HCO3-), with smaller amounts dissolved in plasma or bound to hemoglobin as carbaminohemoglobin.
Q: How does altitude affect the oxygen-carrying capacity of blood?
A:
At higher altitudes, the lower atmospheric pressure results in less oxygen being available, leading to a decrease in the oxygen-carrying capacity of the blood. The body adapts through various mechanisms, including increasing red blood cell production and reducing hemoglobin's affinity for oxygen, to compensate for the reduced oxygen levels.
Q: Why is the diffusion of gases important in respiration?
A:
Diffusion of gases, specifically oxygen and carbon dioxide, is crucial in respiration because it enables the exchange of these gases between the lungs and the bloodstream, and subsequently between the blood and the body's tissues, supporting cellular respiration and survival.
Q: What is the Bohr effect and how does it influence oxygen transport?
A:
The Bohr effect describes how increased carbon dioxide (CO2) levels and decreased pH (increased acidity) in blood reduce hemoglobin's affinity for oxygen, facilitating oxygen unloading to tissues in need.
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