Class 11 Biology (NCERT / JAC Board)

1. What is the average breathing rate of a healthy adult human at rest?

• A. 12 to 16 times/minute
• B. 20 to 25 times/minute
• C. 72 times/minute
• D. 5 to 8 times/minute

2. Tidal Volume (TV) in a healthy human is approximately:

• A. 500 mL
• B. 1000 mL
• C. 2500 mL
• D. 1200 mL

3. The maximum volume of air a person can breathe in after a forced expiration is called:

• A. Vital Capacity (VC)
• B. Tidal Volume (TV)
• C. Total Lung Capacity (TLC)
• D. Residual Volume (RV)

4. The volume of air that remains in the lungs even after a forcible expiration is termed as:

• A. Residual Volume (RV)
• B. Tidal Volume (TV)
• C. Inspiratory Reserve Volume (IRV)
• D. Expiratory Reserve Volume (ERV)

5. Which enzyme present in high concentration in red blood cells facilitates the transport of CO2?

• A. Carbonic anhydrase
• B. Thrombokinase
• C. Pepsin
• D. Carboxypeptidase

6. What percentage of O2 is transported by RBCs in the blood?

• A. 97%
• B. 3%
• C. 70%
• D. 20-25%

7. Carbon dioxide is primarily transported in human blood in the form of:

• A. Bicarbonate ions
• B. Carbamino-haemoglobin
• C. Dissolved gas in plasma
• D. Carbon monoxide

8. The partial pressure of oxygen (pO2) in alveoli is:

• A. 104 mm Hg
• B. 40 mm Hg
• C. 95 mm Hg
• D. 159 mm Hg

9. The Oxygen-Hemoglobin dissociation curve shifts to the right under which of the following conditions?

• A. High pCO2, high H+ concentration, and high temperature
• B. Low pCO2, low H+ concentration, and low temperature
• C. High pO2 and low pCO2
• D. Low temperature and low pCO2

10. Pneumotaxic centre which can moderate the functions of the respiratory rhythm centre is located in:

• A. Pons region of brain
• B. Medulla oblongata
• C. Cerebellum
• D. Hypothalamus

11. Chronic respiratory disorder caused mainly by cigarette smoking, characterized by damage to alveolar walls, is:

• A. Emphysema
• B. Asthma
• C. Occupational Respiratory Disorder
• D. Bronchitis

12. Respiratory rhythm center that primarily regulates basic respiratory rhythm is situated in:

• A. Medulla region of brain
• B. Pons region
• C. Midbrain
• D. Thalamus

13. The shape of the oxygen-haemoglobin dissociation curve is:

• A. Sigmoid
• B. Parabolic
• C. Linear
• D. Hyperbolic

14. What amount of O2 is delivered to tissues by every 100 mL of oxygenated blood under normal physiological conditions?

• A. 5 mL
• B. 4 mL
• C. 15 mL
• D. 20 mL

15. Every 100 mL of deoxygenated blood delivers approximately how much CO2 to the alveoli?

• A. 4 mL
• B. 5 mL
• C. 20 mL
• D. 10 mL

16. The cartilaginous ring structures that support the trachea and prevent it from collapsing are:

• A. Incomplete C-shaped C-cartilages
• B. Complete circular rings
• C. Bony rings
• D. Fibrous tissue rings

17. Trachea divides into right and left primary bronchi at the level of which thoracic vertebra?

• A. 5th thoracic vertebra
• B. 3rd thoracic vertebra
• C. 7th thoracic vertebra
• D. 12th thoracic vertebra

18. The double-layered membrane covering the human lungs is called:

• A. Pleura
• B. Pericardium
• C. Peritoneum
• D. Glisson's capsule

19. During inspiration, contraction of diaphragm leads to an increase in thoracic volume in the:

• A. Antero-posterior axis
• B. Dorso-ventral axis
• C. Lateral axis
• D. Vertical axis only

20. Contraction of external intercostal muscles lifts the ribs and sternum causing an increase in thoracic volume in the:

• A. Dorso-ventral axis
• B. Antero-posterior axis
• C. Longitudinal axis
• D. Transverse axis

21. Functional Residual Capacity (FRC) is equal to:

• A. ERV + RV
• B. TV + IRV
• C. VC + RV
• D. ERV + TV

22. What is the partial pressure of CO2 (pCO2) in deoxygenated blood?

• A. 45 mm Hg
• B. 40 mm Hg
• C. 104 mm Hg
• D. 0.3 mm Hg

23. Which respiratory organ is used by earthworms for gaseous exchange?

• A. Moist cuticle (skin)
• B. Tracheal tubes
• C. Gills
• D. Book lungs

24. Tracheal tubes for gas exchange are characteristic respiratory organs of:

• A. Insects
• B. Fishes
• C. Aquatic molluscs
• D. Flatworms

25. The diffusion membrane through which gaseous exchange occurs in alveoli consists of how many layers?

• A. 3 layers
• B. 2 layers
• C. 4 layers
• D. 1 layer

26. Chemosensitive area located adjacent to the rhythm center is highly sensitive to:

• A. CO2 and H+ ions
• B. O2 concentration only
• C. N2 gas
• D. Glucose levels

27. Which condition causes difficulty in breathing along with wheezing due to inflammation of bronchi and bronchioles?

• A. Asthma
• B. Emphysema
• C. Silicosis
• D. Asbestosis

28. Occupational respiratory disorders like silicosis and asbestosis lead to severe lung damage mainly via:

• A. Fibrosis (proliferation of fibrous tissues)
• B. Breakdown of alveolar walls
• C. Bacterial infection
• D. Excess mucus accumulation

29. Total Lung Capacity (TLC) is represented by:

• A. Vital Capacity + Residual Volume
• B. Tidal Volume + Residual Volume
• C. Inspiratory Capacity + Expiratory Reserve Volume
• D. Expiratory Reserve Volume + Residual Volume

30. What is the role of oxygen in the regulation of respiratory rhythm under normal conditions?

• A. Quite insignificant
• B. Primary driving force
• C. Same as CO2
• D. Controls pneumotaxic centre directly