NCERT Exemplar for Class 11 Biology Chapter-17 (Book Solutions)

Multiple Choice Questions (MCQs)

1. Respiration in insects is called direct because

a. The cell exchanges O2/ CO2 directly with the air in the tubes

b. The tissues exchange O2/ CO2 directly with coelomic fluid

c. The tissues exchange O2/ CO2 directly with the air outside through body surface

d. Tracheal tubes exchange O2/ CO2 directly with the haemocoel which then exchanged with tissues

Ans: Option (a) is the answer. Insects' respiration is unaffected by their coelomic fluid. They breathe using a tracheal system, which allows the cells to directly exchange O2/CO2 with the air in the tubes.

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

Ans: Option (d) is the answer. Our respiratory system humidifies the air, warms up the air and exchanges gases. So, the correct answer is to clean up the air.

3. A person suffers punctures in his chest cavity in an accident without any damage to the lungs. Its effect could be

a. Reduced breathing rate

b. Rapid increase in breathing rate

c. No change in respiration

d. Cessation of breathing

Ans: Option (d) is the answer. The chest cavity appears to work like an air-tight chamber. Any puncture will hamper inflation or deflation and thus breathing will stop.

4. It is known that exposure to carbon monoxide is harmful to animals because

a. It reduces CO2 transport

b. It reduces O2 transport

c. It increases CO2 transport

d. It increases O2 transport

Ans: Option (b) is the answer. Carbon monoxide poisoning is detrimental to animals because it reduces oxygen transfer. Carbon monoxide attaches to the blood's haemoglobin, leaving oxygen behind. Because the cells are unable to breathe in this manner, they are unable to live for an extended period of time.

5. Mark the true statement among the following with reference to 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 processes

Ans: Option (b) is the answer. Expiration is the process of removing stale air from the lungs. Expiration is a natural passive process in which the inspiratory muscles relax. 'Inspiration is an active process, whereas expiration is a passive process,' is the proper answer.

6. A person breathes in some volume of air by forced inspiration after having a forced expiration. This quantity of air taken in is

a. Total lung capacity

b. Tidal volume

c. Vital capacity

d. Inspiratory capacity

Ans: Option (c) is the answer. The greatest volume of air a person can breathe in after a forced expiration or maximum amount of air a person can breathe in after a forced inspiration is referred to as vital capacity.

7. Mark the incorrect statement in context to O2 binding to Hb

a. Higher pH

b. Lower temperature

c. Lower pCO2

d. Higher PO2

Ans: Option (a) is the answer. 

Factors that increase the affinity of oxygen haemoglobin binding include:

(i)The partial pressure of oxygen increases;

(ii) the partial pressure of carbon dioxide decreases.

(iii) Low pH due to high hydrogen ion concentration

(iv) Extremely low temperatures

As a result, the correct answer is 'Higher pH'.

8. Which of the following statements is incorrect regarding the respiratory system?

a. Each terminal bronchiole give rise to a network of bronchi.

b. The alveoli are highly vascularised.

c. The lungs are covered by a double-layered membrane.

d. The pleural fluid reduces friction on the lung surface.

Ans: Option (a) is the answer. The windpipe, also known as the trachea, is a straight tube that runs from the throat to the chest cavity. It separates into light and left bronchi. Secondary bronchi, tertiary bronchi, and bronchioles are the branches formed by the recurrent divisions of these bronchi. Bronchioles are the bronchi's branching points. As a result, bronchioles emerge from bronchi, not the other way around. As a result, this choice is accurate.

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

Ans: Option (b) is the answer. Emphysema is a disorder in which the alveolar wall breaks down and the respiratory region shrinks as a result of smoking.

10. Respiratory process is regulated by certain specialized centres in the brain. One of the following centres can reduce the inspiratory duration upon stimulation

a. Medullary inspiratory centre

b. Pneumotaxic centre

c. Apneustic centre

d. Chemosensitive centre

Ans: Option (b) is the answer. Pons Varolii's pneumotaxic centre is placed in the dorsal region of the organism. Because it is known to restrict the duration of inspiration, it is nicknamed a switch-off point of breathing. The breathing rate is regulated by this centre, which controls the respiratory rhythm centre.

11. CO2 dissociates from carbamino haemoglobin when

a. pCO2 is high & pO2 is low

b. pO2 is high and pCO2 is low

c. pCO2 and pO2 are equal

d. None of the above

Ans: Option (b) is the answer. High PO2 and low PCO2 in the lung blood capillaries favours separation of CO2 from carbamino haemoglobin.

12. In breathing movements, air volume can be estimated by

a. Stethoscope

b. Hygrometer

c. Sphygmomanometer

d. Spirometer

Ans: Option (d) is the answer. Stethoscope is used for hearing sounds from the chest. A hygrometer is a device that measures the density of liquid. Sphygmomanometer is used for measuring blood pressure.

13. From the following relationships between respiratory volume and capacities and mark the correct answer

i. Inspiratory capacity (IC) = Tidal Volume + Residual Volume

ii. Vital Capacity (VC) = Tidal Volume (TV) + Inspiratory Reserve Volume (IRV) + Expiratory Reserve Volume (ERV).

iii. Residual Volume (RV) = Vital Capacity (VC) – Inspiratory Reserve Volume (IRV)

iv. Tidal Volume (TV) = Inspiratory Capacity (IC) – Inspiratory Reserve Volume (IRV)

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

Ans: Option (b) is the answer. 

(i) Inspiratory Capacity (IC) = Tidal Volume + Residual Volume - INCORRECT

(ii) Vital Capacity (VC) = Tidal Volume (TV) + Inspiratory Reserve Volume (IRV) + Expiratory Reserve Volume (ERV) - INCORRECT

(iii) Residual Volume (RV) = Vital Capacity (VC) - inspiratory Reserve Volume (IRV) - INCORRECT

(iv) Tidal Volume(TV) = Inspiratory Capacity (IC) - Inspiratory Reserve Volume (IRV) - CORRECT

So, the correct answer is '(i) Incorrect, (ii) Correct, (iii) Incorrect, (iv) Correct'.

14. The oxygen – haemoglobin dissociation curve will show a right shift in case of

a. High pCO2

b. High pO2

c. Low pCO2

d. Less H+ concentration

Ans: Option (a) is the answer. Several factors can cause the oxygen haemoglobin dissociation curve to move to the right or left. When there is high PCO2, low PO2, high H+ concentration, and high temperature, the oxygen-haemoglobin curve shifts to the right.

15. Match the following and mark the correct options

Options:

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-ii, C-i.v, D-iii

Ans: Option (b) is the answer. Gills are respiratory organs found in both fish and aquatic arthropods (such as crustaceans). The cuticle of earthworms is wet, whereas the respiratory organs of birds and reptiles are lungs.

VERY SHORT ANSWER TYPE QUESTIONS

1. Define the following terms?

a. Tidal volume

Ans: Tidal volume is the amount of air inhaled and expelled during a typical breathing cycle without any forced breathing.

b. Residual volume

Ans: Residual volume refers to the amount of air that remains in the lungs following forceful expiration.

c. Asthma

Ans: It is an inflammatory disease of the airways of the lungs

2. A fluid-filled double membranous layer surrounds the lungs. Name it and mention its important function.

Ans: A fluid-filled double membranous layer that surrounds the lungs is called Pleura.  It reduces friction on lungs and acts as a protective covering of the lungs.

3. Name the primary site of the exchange of gases in our body?

Ans: The primary site of the exchange of gases in our body is Alveoli.

4. Cigarette smoking causes emphysema. Give reason.

Ans: Because of the presence of several hazardous compounds like nicotine, tar, and sulphur, excessive cigarette smoking causes Emphysema. This causes damage to the walls of the alveoli.

5. What is the amount of O2 supplied to tissues through every 100 ml. of oxygenated blood under normal physiological conditions?

Ans: Under normal physiological settings, 5 ml of oxygenated blood is delivered to tissues for every 100 ml of oxygenated blood.

6. A major percentage (97%) of O2 is transported by RBCs in the blood. How does the remaining percentage (3%) of O2 transport?

Ans: A major percentage (97%) of O2 is transported by RBCs in the blood and the remaining percentage (3%) of O2 is transported through plasma.

7. Arrange the following terms based on their volumes in an ascending order

a. Tidal Volume (TV)

b. Residual Volume (RV)

c. Inspiratory Reserve Volume (IRV)

d. Expiratory Capacity (EC)

Ans:  The arrangement of the terms based on their volumes is as follows- Tidal Volume (TV) < Residual Volume (RV) < Expiratory Capacity (EC) < Inspiratory Reserve Volume (IRV).

8. Complete the missing terms

a. Inspiratory Capacity (IC) = _____ +IRV

Ans: Inspiratory Capacity (IC) = TV + IRV

The volume of air that can be inspired after a normal, quiet expiration is equal to tidal volume + inspiratory reserve volume in inspiratory capacity.

b. ___________________ = TV + ERV

Ans: EC = TV + ERV It is the total amount of air exhaled after maximal inhalation.

c. Functional Residual Capacity (FRC) = ERV + ___

Ans:  Functional Residual Capacity (FRC) = ERV + RV. The volume of air in the lungs at the end of passive expiration is known as functional residual capacity (FRC).

9. Name the organs of respiration in the following organisms:

a. Flatworm _________________________________________

Ans:  Flatworms have no specialized respiratory system; gases simply diffuse across the body wall.

b. Birds _____________________________________________

Ans:  Birds respire through lungs. Air enters the trachea through the nose and fills the posterior air sacs. When you exhale, air leaves the posterior air sacs and enters the lungs. (The gas exchange occurs in the lungs, where carbon dioxide is exchanged for new oxygen.)

c. Frog ______________________________________________

Ans: Frog respire through Lungs and moist skin.

d. Cockroach _______________________________________

Ans: Cockroaches respire through Tracheal tubes.

10. Name the important parts involved in creating a pressure gradient between lungs and the atmosphere during normal respiration.

Ans: The important parts involved in creating a pressure gradient between lungs and the atmosphere during normal respiration are-

1. Diaphragm

2. Internal Intercostal Muscles of the ribs

3. External Intercostal Muscles of the ribs

SHORT ANSWER TYPE QUESTIONS

1. State the different modes of CO2 transport in the blood.

Ans: The different modes of CO2 transport in the blood are-

1. Carbon dioxide mixes with water in red blood cells to generate carbonic acid. It's an unstable state that breaks down into hydrogen and bicarbonate ions.

2. Bicarbonate ions, which are made up of carbon dioxide, are likewise carried by plasma.

2. Compared to O2, the diffusion rate of CO2 through the diffusion membrane per unit difference in partial pressure is much higher. Explain.

Ans: Carbon dioxide has a much higher solubility than oxygen, hence its diffusion rate across the diffusion membrane is much higher per unit change in partial pressure.

3. For completion of the respiration process, write the given steps in sequential manner

a. Diffusion of gases (O2 and CO2) across the alveolar membrane.

b. Transport of gases by blood.

c. Utilisation of O2 by the cells for catabolic reactions and resultant release of CO2.

d. Pulmonary ventilation by which atmospheric air is drawn in and CO2 rich alveolar air is released out.

e. Diffusion of O2 and CO2 between blood and tissues.

Ans: The correct sequence would be:

1. Pulmonary ventilation by which atmospheric air is drawn in and CO2 rich alveolar air is released out.

2. Diffusion of gases (O2 and CO2) across the alveolar membrane.

3. Transport of gases by blood.

4. Diffusion of O2 and CO2 between blood and tissues.

5. Utilisation of O2 by the cells for catabolic reactions and resultant release of CO2.

4. Differentiate between

a. Inspiratory and expiratory reserve volume

Ans: The maximum volume of air that can be breathed after normal inspiration is the inspiratory reserve volume, whereas the greatest volume of air that can be expelled after normal expiration is the expiratory reserve volume.

b. Vital capacity and total lung capacity

Ans: Total lung capacity is the volume of air in the lungs after maximal inspiration, whereas vital capacity is the greatest volume of air that can be expelled following normal inspiration.

c. Emphysema and occupational respiratory disorder

Ans: Emphysema is produced by the development of fibrous connective tissue in the upper lungs, whereas occupational respiratory illness is caused by the damage to the alveolar walls.

LONG ANSWER TYPE QUESTIONS

1. Explain the transport of O2 and CO2 between alveoli and tissue with a diagram.

Ans: Transportation of Oxygen.

1. The oxygen we breathe reaches our alveoli.

2. Because the partial pressure of oxygen in alveoli is higher, oxygen diffuses to capillaries and mixes with haemoglobin to create oxyhaemoglobin.

3. Oxygenated blood is delivered to an organ with a lower partial pressure than alveoli.

4. In these organs, the connection between oxygen and haemoglobin will be fragile and will break, allowing oxygen to enter the organs.

Transportation of Carbon Dioxide:

1. Various organs emit carbon dioxide, which is transported to the alveoli via capillaries, which have a lower intrapulmonary pressure than the organs.

2. Because the intrapulmonary pressure in the alveoli is lower than in the capillaries, carbon dioxide will pass from the capillaries to the alveoli.

3. Carbon dioxide mixes with water in red blood cells to generate carbonic acid. It's an unstable state that breaks down into hydrogen and bicarbonate ions.

4. Bicarbonate ions, which are carbon dioxide ions, are likewise carried by plasma.

2. Explain the mechanism of breathing with neatly labelled sketches.

Ans: Mainly two processes are involved in breathing

A. Inspiration

B. Expiration

A. Inspiration: The process of taking in external air or oxygen into the lungs is known as inhalation. It begins when the diaphragm contracts, causing the thoracic chamber to expand. The intercostal muscles then contract, drawing the ribs and sternum together, increasing the capacity of the thoracic chamber. The increased thoracic chamber volume also raises the pulmonary volume.

This lowers the intrapulmonary pressure below atmospheric pressure, allowing external oxygen to enter the lungs, a process known as inspiration.

B. Expiration: When the diaphragm relaxes, exhalation begins. As a result, the volume of the thoracic chamber is reduced. After that, the intercostal muscles relax, which causes the ribs and sternum to relax as well, reducing the volume of the thoracic chamber. This causes the pulmonary pressure to drop below atmospheric pressure, causing exhalation of external oxygen.

3. Explain the role of the neural system in the regulation of respiration.

Ans: There are various centres in the neural system that plays significant a role in the regulation and control of respiration. Those are:

1. Pneumotaxic centre: It is found in the pons varoli of the brain's dorsal portion (back). It shortens the length of inspiration and changes the pace of respiration.

2. Respiratory Rhythm Centre or Medullary inspiratory Centre: It is present in the medulla of the brain. It regulates the respiratory rhythm.

3. Apneustic centre is present in the lower part of the pons varoli of the brain. It increases the duration of inspiration.

4. Chemosensitive centre is present in the medulla oblongata and the pons area of the brain.

Benefits of solving NCERT Exemplar for Class 11 Biology - Breathing and Exchange of Gases

Biology is a subject that requires both regular revision and practice. For regular revision, a thorough grasp of the NCERT topics is required. For practice, there are several books available in the market but the best book for Biology is NCERT and NCERT exemplar. Be it competitive examinations like NEET or CBSE boards or school exams, the majority of the questions asked are NCERT-based. So, students should study NCERT well.

The questions of NCERT Exemplar are highly logical. Solving the NCERT exemplar questions will help you develop strong concepts. It helps students develop analytical skills and gives them a real feel of the examination. Students become more accustomed to the exam pattern and the marking scheme. They can understand which topics are necessary from the examination point of view. Thus, they can carry out their revisions faster. 

Regular question solving reduces mistakes while solving questions. Students learn better time management as well.

Many students have doubts while solving certain questions of the NCERT exemplar. Therefore we have provided solutions to all the questions of NCERT Exemplar for Class 11 Biology - Breathing and Exchange of Gases in PDF form which is free to download.

Some of the topics which have been covered in the chapter Breathing and Exchange of Gases are:

• Respiration

• Steps of Respirations

• Mechanism of Breathing

• Respiratory Volumes and Capacities

• Exchange of Gases

• Transport of Gases

• Transport of Carbon Dioxide

• Regulation of Respiration

• Disorders of Respiration

We require energy from food to perform many activities. The catabolism of components of food, for example, proteins, carbohydrates, fats, etc provides this energy. For this process to take place the body requires a continuous exchange of gases.  Oxygen from the air is taken in while carbon dioxide produced is taken out. Oxygen is required for the breakdown of food and carbon dioxide is freed in the process. The process of breathing and respiration has been explained in a very easy way in this chapter.

Why is Vedantu ideal for you?

If you are someone who wants to fall in love with learning, Vedantu is the place for you. We ensure that students enjoy the process of learning and that it is not a forced thing for them. Education is beautiful and we want students to be awed by its wonders not to run away from it. 

We make use of learning aids like flowcharts, diagrams, summary sheets, etc, to make learning effective for students. Our classes are online and interactive which you can attend from any corner of the world if you have access to an internet connection. 

With our online classes, you are in charge of how fast or slow you want to learn. You can attend online classes or watch their recordings at your own pace. We also have a vast question bank of NCERT based questions and PYQs for examinations like JEE, NEET, CBSE, or international examinations. You can also take online tests of the above-mentioned examinations with a real exam-like timer and marking scheme. You can also see where you stand among the rest of your peers with our detailed analysis after every test.

So, wait no more. Join the revolutionary process of learning today with Vedantu!

Solving the NCERT Exemplar is very important for examinations like JEE, NEET, CBSE, or international examinations. The majority of the questions in these examinations are NCERT based. Here, you can find the solutions to NCERT Exemplar for Class 11 Biology - Breathing and Exchange of Gases. 

The solutions are provided in the form of PDFs and are free to download. All the solutions to  NCERT Exemplar for Class 11 Biology can be found on the website. Going through the solutions will help students clear their doubts regarding NCERT Exemplar for Class 11 Biology. Get this solution today from Vedantu and complete your study material.