Breathing and Exchange of Gases Mock Test – Class 11 Biology

1. A graph plots cumulative air volume moved against time for two breathing patterns with the same tidal volume of . Line P represents , and line Q represents . Q has the steeper slope. This indicates that:

2. A blockage completely closes the right primary bronchus while the trachea and left primary bronchus remain open. The most direct consequence is:

3. The relevant respiratory values are shown below.

Which pair of directions is supported?

4. Blood entering pulmonary capillaries has low and high . After passing an alveolus, it leaves with higher and lower , then reaches systemic tissues where the opposite changes occur. Which circuit description is correct?

5. The maximum volume inspired after a normal expiration is represented symbolically by:

6. In an experimental preparation, the diaphragm and external intercostal muscles can be activated separately.

The results most strongly support the conclusion that:

7. Sample P contains haemoglobin molecules at oxygen saturation. Sample Q contains haemoglobin molecules at saturation. Each haemoglobin molecule can bind four molecules. Which sample has more haemoglobin-bound oxygen, and by how many molecules?

8. A healthy person's exchange with the environment must continue even between meals. The main biological reason is that body cells:

9. Two groups perform the same dusty industrial task for the same duration. Group P consistently wears effective protective masks, while Group Q does not. Q inhales more dust and later shows more respiratory inflammation. The strongest supported inference is:

10. A student adds the upper values of the carbon-dioxide transport categories and obtains:

Which interpretation is most appropriate?

11. Site P has high and low , while Site Q has low and high . Which carbamino-haemoglobin pattern is expected?

12. A frog and a reptile both experience a temporary reduction in pulmonary ventilation while their external body surfaces remain moist. Which prediction is most appropriate from the stated respiratory arrangements?

13. Across a stated volume of blood, a total of of oxygen is transported. Using the approximate transport fractions, how much is carried by red blood cells and how much remains dissolved in plasma?

14. During intense muscular activity, a tissue region develops lower , higher , higher concentration and higher temperature than a resting region. Blood entering both regions initially has similar oxygenation. What is expected in the active region?

15. Assertion: The thoracic chamber is bounded by the vertebral column, sternum, ribs and diaphragm.
Reason: All four structures are segments of the conducting airway through which inspired air passes.

16. A lung-volume graph uses a theoretical zero-air reference on the vertical axis. The maximum inspiratory peak is , and the lowest voluntary expiratory point is . Which interpretation is valid?

17. Order the events in the outward pathway of metabolically produced carbon dioxide.
P. Carbon dioxide is produced in tissues with near .
Q. It diffuses into systemic blood with near .
R. Deoxygenated blood reaches the lungs with near .
S. Carbon dioxide diffuses into alveoli with near .

18. Evaluate the following statements about oxygen-haemoglobin association.
I. is the primary factor influencing oxygen binding.
II. , concentration and temperature modify association and dissociation.
III. Oxygen binding is controlled only by temperature and is independent of .
IV. Conditions surrounding haemoglobin can favour either loading or unloading.

19. If cartilaginous support of the trachea is severely weakened while alveolar structure remains normal, the earliest likely problem is:

20. During an attempted inspiration with an open airway, atmospheric pressure is and intra-pulmonary pressure is . At the same moment, alveolar is experimentally held at and incoming pulmonary blood has . Which paired directions follow from the stated gradients?

21. Consider the following statements.
I. Tidal volume is the air inspired or expired during a normal breath.
II. Its approximate value in a healthy person is .
III. Minute respiratory volume can be obtained by multiplying tidal volume by respiratory frequency.
IV. Minute respiratory volume is the air remaining after forcible expiration.

22. Four individuals have the same of but different residual volumes.

Who has the greatest vital capacity?

23. The conversion pathway that normally produces bicarbonate from tissue carbon dioxide is strongly impaired, while dissolved transport and carbamino-haemoglobin formation remain unchanged. Which consequence is most likely?

24. In a blood preparation exposed to tissue-like high , red-cell carbonic anhydrase activity is strongly inhibited and the carbon-dioxide-binding sites of haemoglobin are blocked. Plasma remains present. Which inference about carbon-dioxide carriage is justified?

25. An oxygen molecule moves from alveolar air toward a red blood cell in a pulmonary capillary. Arrange the following structures in the order crossed.
P. Capillary endothelium
Q. Basement substance
R. Alveolar squamous epithelium
S. Capillary blood

26. When intra-pulmonary pressure becomes slightly lower than atmospheric pressure, air normally:

27. Increasing the strength of signals from the pneumotaxic centre shortens the duration of inspiration. Which respiratory change is most directly supported?

28. Equal haemoglobin samples are maintained at the same , and temperature. Sample P has a lower concentration and reaches saturation, whereas Sample Q has a higher concentration and reaches saturation. What is the strongest inference?

29. Assertion: No net airflow occurs when intra-pulmonary pressure equals atmospheric pressure.
Reason: Respiratory air normally moves from a region of lower pressure toward a region of higher pressure.

30. A person has , , and . What are and , respectively?

31. Assertion: The respiratory pathway continues from the pharynx through the larynx.
Reason: Part of the pharynx serves as a common passage for food and air.

32. Two artificial exchange membranes have equal surface area and separate identical gas mixtures under the same partial-pressure gradient. Membrane P is thin, while membrane Q is several times thicker. Less gas crosses Q in the same interval. The strongest inference is that:

33. A frog can use lungs and can additionally exchange gases through its moist skin. This shows that its respiratory arrangement is ______.

34. The following observations are recorded in sequence.

Which respiratory step is affected first?

35. After completing a normal expiration, a person forcibly expels an additional of air before reaching the lowest voluntary lung-volume level. The additional expelled volume is:

36. Assertion: Quiet expiration normally follows relaxation of the diaphragm and intercostal muscles.
Reason: Their relaxation reduces thoracic and pulmonary volumes, raising intra-pulmonary pressure above atmospheric pressure.

37. One hundred haemoglobin molecules leave the lungs at saturation. They pass through resting tissue and active tissue in separate trials, leaving at and saturation, respectively. How many additional molecules are released in the active-tissue trial?

38. If the epiglottis fails to cover the glottis during swallowing, the most immediate risk is that:

39. Match each respiratory quantity with its classification. Column II entries may be reused.

40. Assertion: Under normal conditions, carbon dioxide diffuses from alveoli into deoxygenated pulmonary blood.
Reason: Deoxygenated blood has a of about , while alveolar air has about .

41. Three respiratory disorders are compared.

Which identification is correct?

42. Evaluate the following statements about partial pressure.
I. It is the pressure contributed by one gas in a mixture.
II. and denote the individual pressure contributions of oxygen and carbon dioxide.
III. A gas has the same partial pressure in the atmosphere, alveoli, blood and tissues.
IV. Partial-pressure differences help determine the direction of respiratory-gas diffusion.

43. The same circulating blood volume passes through systemic tissues and later through the lungs at for . Using the normal reference values, how much oxygen is delivered to tissues and how much carbon dioxide is delivered to alveoli?

44. Person P breathes with . Person Q breathes with . How much total tidal air does each move in ?

45. Use the movement pattern described below. The dome-shaped diaphragm becomes flatter, while the ribs and sternum move upward and outward. This combination indicates:

46. Air sampled near the terminal bronchioles contains fewer foreign particles than inspired air and has normal moisture, but its temperature remains far below body temperature. Airflow and alveolar structure are normal. Which conducting function is selectively impaired?

47. A preparation contains haemoglobin molecules. Twenty-five molecules carry four molecules each, fifty carry two each, and twenty-five carry none. What is the total oxygen load and the percentage of maximum carrying capacity?

48. Match each quantity with its defining respiratory state or movement. A Column II entry is used once.

49. In a terrestrial arthropod, the openings leading into branching tracheal tubes are blocked while circulation continues normally. Tissue oxygen availability falls rapidly. Which inference is best supported?

50. Arrange the following events in the normal oxygen-transport sequence.
P. Oxyhaemoglobin forms under alveolar conditions.
Q. Oxygen diffuses from alveoli into pulmonary blood.
R. Blood carries oxyhaemoglobin toward systemic tissues.
S. Tissue conditions promote oxyhaemoglobin dissociation.
T. Oxygen enters tissue cells.