Breathing and Exchange of Gases Class 11 Biology Exam Questions

Exam Questions Class 11

Please refer to Breathing and Exchange of Gases Class 11 Biology Exam Questions provided below. These questions and answers for Class 11 Biology have been designed based on the past trend of questions and important topics in your class 11 Biology books. You should go through all Class 11 Biology Important Questions provided by our teachers which will help you to get more marks in upcoming exams.

Class 11 Biology Exam Questions Breathing and Exchange of Gases

Class 11 Biology students should read and understand the important questions and answers provided below for Breathing and Exchange of Gases which will help them to understand all important and difficult topics.

Very Short Answer Type Questions:

Question. Name the primary site of exchange of gases in our body?
Ans. The primary site for the exchange of gases in our body is alveoli. There are 300 millions of alveoli collectively in both the lungs. These alveoli have very thin wall consisting of squamous epithelium. With extensive network of blood capillaries.

Breathing and Exchange of Gases Class 11 Biology Exam Questions

Question. Name the important parts involved in creating a pressure gradient between lungs and the atmosphere during normal respiration.
Ans. The diaphragm and a specialised set of external and intercostals muscles between the ribs, help in the generation of pressure gradient during normal respiration.

Breathing and Exchange of Gases Class 11 Biology Exam Questions

Question. Cigarette smoking causes emphysema. Give reason.
Ans. Emphysema is a chronic disorder of respiratory system, where inflation or abnormal distension of alveolar wall occurs. Cigarette smoking and the inhalation of other smoke or toxic substances over a period of time causes the damaging of septa between the alveoli, and of its elastic tissue is replaced by the connective tissue in lungs.
Hence, the respiratory surface decreases, thus causing the emphysema. It causes shortness of breath, production of sputum, chronic bronchitis, etc.

Question. Name the organs of respiration in the following organisms.
(a) Flatworm ……… (b) Birds ………
(c) Frog ……… (d) Cockroach ………
Ans. (a) Flatworm General body surface (b) Birds Lungs
(c) Frog Lungs and moist skin (d) Cockroach Tracheal tubes

Question. What is the amount of O2 supplied to tissues through every 100 mL of oxygenated blood under normal physiological conditions?
Ans. Every 100 mL of oxygenated blood can deliver around 5 mL of O2 to the tissue under normal physiological conditions.

Question. 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, and fluid is pleural fluid in between them. The outer pleural membrane is in close contact with the thoracic lining whereas, the inner pleural membrane is in contact with the lung surface.
These collectively reduce friction on lung’s surface.

Breathing and Exchange of Gases Class 11 Biology Exam Questions

Question. 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. (d) Expiratory Capacity (EC) Approximate volume is 1000 mL.
(b) Residual Volume (RV) Approximate volume is 1200 mL.
(c) Inspiratory Reserve Volume (IRV) Approximate volume is 2500 to 3000mL.
(a) Tidal Volume(TV) Approximate volume is 6000 to 8000 mL.

Breathing and Exchange of Gases Class 11 Biology Exam Questions

Question. A major percentage (97%) of O2 is transported by RBCs in the blood. How does the remaining percentage (3%) of O2 transported?
Ans. About 97% ofO2 is transported by RBCs in the blood. The remaining 3% of O2 is carried in a dissolved state through the plasma.

Question. Complete the missing terms
(a) Inspiratory Capacity (IC) =… + IRV
(b) … = TV + ERV
(c) Functional Residual Capacity (FRC) = ERV + …
Ans. (a) Inspiratory Capacity (IC) = (TV)+ (IRV)Tidal Volume. Inspiratory Reserve Volume
(b) Expiratory Capacity (EC) = (TV + ERV)Tidal Volume. Expiratory Reserve Volume
(c) Functional Residual Capacity (FRC) = (ERV)Expiratory + (RV)Reserve Volume. Residual Volume

Question. Define the following terms?
(a) Tidal volume (b) Residual volume
(c) Asthma
Ans. (a) Tidal Volume (TV) is the volume of air inspired or expired during normal breath. This is about 500 mL, i.e., a healthy man inspire or expire about 6000 to 8000 mL of air per minute.
(b) Residual Volume (RV) is the volume of air remaining in the lungs even after a forcible expiration. It is about 1100 mL to 1200 mL.
(c) Asthma It is a disease caused due to an allergic reaction to foreign substances. The major symptoms are difficulty in breathing causing wheezing and coughing. Due to the inflammation of bronchi.

Short Answer Type Questions:

Question. Compared to O2, diffusion rate of CO2 through the diffusion membrane per unit difference in partial pressure is much higher. Explain.
Ans. As, the solubility rate of CO2 is 20-25 times higher than that of the O2, the amount of CO2 that can diffuse through the diffusion membrane per unit difference in partial pressure is much higher compared to that of O2.

Question. For completion of respiration process, write the given steps in sequential manner.
(a) Diffusion of gases (O2 and CO2) across 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. (d) Pulmonary ventilation by which atmospheric air is drawn in and CO2 rich alveolar air is released out.
(a) Diffusion of gases (O2 and CO2) across alveolar membrane.
(b) Transport of gases by blood.
(c) Diffusion of O2 and CO2 between blood and tissues.
(e) Utilisation of O2 by the cells for catabolic reactions and resultant release of CO2.

Question. State the different modes of CO2 transport in blood.
Ans. Carbon dioxide is carried by the blood in three forms
(i) In Dissolved State Under normal temperature and pressure, about 7% of CO2 is carried by physical solution.
(ii) As Carbamino Compounds CO2 binds directly with Hb to form an unstable compound carbaminocompounds (CO2Hb) About 23% CO2 is transported in this form.
When pCO2 is high and pO2 is low as in the tissues, more binding of carbon-dioxide occurs whereas, when pCO2 is low and pO2 is high as in alveol as tissue dissociation of CO2 from carbamino-haemoglobin takes place.

Breathing and Exchange of Gases Class 11 Biology Exam Questions

(iii) As Bicarbonate Ions CO2 reacts with water to form carbonic acid (H2CO3) in the presence of carbonic anhydrase in RBC. H2CO3 dissociates into hydrogen and bicarbonate ions (HCO3).
The whole reaction proceeds as follows

Breathing and Exchange of Gases Class 11 Biology Exam Questions

The carbonic anhydrase reaction mainly occur in RBC as it contain high concentration of enzyme carbonic anhydrase and minute quantity of it is present in plasma too.

Question. Differentiate between
(a) Inspiratory and expiratory reserve volume
(b) Vital capacity and total lung capacity.
(c) Emphysema and occupational respiratory disorder.
Ans. Difference between these are as follows

Breathing and Exchange of Gases Class 11 Biology Exam Questions
Breathing and Exchange of Gases Class 11 Biology Exam Questions

Long Answer Type Questions:

Question. Explain the mechanism of breathing with neat labelled sketches.
Ans. Mechanism of Breathing Breathing involves two stages, inspiration during which atmospheric air is drawn in and expiration by which the alveolar air is released out.
The movement of air into and out of the lungs is carried out by creating a pressure gradient between the lungs and the atmosphere, the help of diaphragm and inter costal muscles.

Breathing and Exchange of Gases Class 11 Biology Exam Questions

Question. Explain the role of neural system in regulation of respiration.
Ans. Human beings have a significant ability to maintain and moderate the respiratory rhythm to suit the demands of the body tissue. This is done by the neural system.
Respiration regulated by neural system in following ways/ manress
(i) A specialised centre present in the medulla region of the brain called respiratory rhythm centre is primarily responsible in regulating respiration process. Another centre present in the pons region of the brain called pneumotaxic centre, can moderate the functions of the respiratory rhythm centre. Neural signal from this centre, can reduce the duration of inspiration and thereby alter the respiratory rate.
(ii) A chemosensitive area is situated adjacent to the rhythm centre which is highly sensitive to CO2 and hydrogen ions. Increase in these substances activates this centre, which in turn signals the rhythm centre to make necessary adjustments in the respiratory process by which these substances can be eliminated.
(iii) Receptors associated with aortic arch and carotid artery also recognise changes in CO2 and H+ concentration and send necessary signals to the rhythm centre for remedial
action because the role of oxygen in the regulation of respiratory rhythm is quite insignificant.

Question. Explain the transport of O2 and CO2 between alveoli and tissue with diagram.
Ans. Representing the transport of O2 and CO2 between alveoli and tisue with diagram

Breathing and Exchange of Gases Class 11 Biology Exam Questions