TRB PG Assistant - Respiration – structures, pigments, gas transport and regulation Online Test (MCQ Quiz)

1. Which of the following is the primary respiratory pigment in most vertebrates?

A) Hemocyanin B) Hemoglobin C) Chlorocruorin D) Myoglobin

2. In which part of the human respiratory system does gas exchange primarily occur?

A) Trachea B) Bronchi C) Alveoli D) Larynx

3. What is the main function of the epiglottis?

A) To produce sound B) To filter air C) To prevent food from entering the trachea D) To warm inhaled air

4. The rate of breathing is primarily regulated by the respiratory center located in which part of the brain?

A) Cerebrum B) Cerebellum C) Medulla Oblongata D) Hypothalamus

5. What is the partial pressure of oxygen (PO2) in deoxygenated blood entering the lungs?

A) About 100 mmHg B) About 40 mmHg C) About 159 mmHg D) About 0.3 mmHg

6. Which respiratory pigment is found in the hemolymph of some arthropods and mollusks, and contains copper instead of iron?

A) Hemoglobin B) Chlorocruorin C) Hemerythrin D) Hemocyanin

7. The Bohr effect describes the influence of which factor on the oxygen-binding affinity of hemoglobin?

A) Temperature B) pH C) Carbon dioxide concentration D) All of the above

8. In fish, gas exchange occurs across which specialized structures?

A) Lungs B) Tracheae C) Gills D) Skin

9. What is the primary mechanism by which carbon dioxide is transported in the blood?

A) Dissolved in plasma B) Bound to hemoglobin C) As bicarbonate ions D) All of the above

10. Which law states that the volume of a gas is inversely proportional to its pressure at a constant temperature?

A) Dalton's Law B) Henry's Law C) Boyle's Law D) Charles's Law

11. The structure responsible for producing vocal sounds is the:

A) Pharynx B) Larynx C) Esophagus D) Nasal cavity

12. What is the role of surfactant in the alveoli?

A) To transport oxygen B) To reduce surface tension and prevent alveolar collapse C) To secrete mucus D) To trigger coughing reflexes

13. Which of the following conditions leads to a decrease in hemoglobin's affinity for oxygen?

A) Increased pH B) Decreased CO2 levels C) Increased temperature D) Increased PO2 in tissues

14. In birds, the respiratory system is unique due to the presence of:

A) Diaphragm B) Alveoli C) Air sacs D) Gills

15. The movement of gases across the respiratory membrane is driven by:

A) Active transport B) Osmosis C) Diffusion D) Facilitated diffusion

16. Which respiratory pigment is found in the blood of some marine worms and contains iron, but is not contained within red blood cells?

A) Hemoglobin B) Hemocyanin C) Chlorocruorin D) Myoglobin

17. The process of breathing in is called:

A) Expiration B) Inspiration C) Respiration D) Ventilation

18. What is the main stimulus that triggers an increase in breathing rate?

A) Low oxygen levels B) High carbon dioxide levels C) Low blood pressure D) High body temperature

19. The enzyme responsible for catalyzing the formation of bicarbonate ions from carbon dioxide and water in red blood cells is called:

A) Catalase B) Carbonic anhydrase C) Hemoglobinase D) Oxidase

20. Which part of the respiratory system acts as a common passage for both food and air?

A) Nasal cavity B) Larynx C) Pharynx D) Trachea

21. Myoglobin is a protein that stores oxygen primarily in which type of tissue?

A) Red blood cells B) Liver cells C) Muscle cells D) Nerve cells

22. What is the partial pressure of oxygen (PO2) in the alveoli?

A) About 40 mmHg B) About 100 mmHg C) About 159 mmHg D) About 0.3 mmHg

23. The ' Haldane effect' describes the influence of oxygen levels on the transport of which gas?

A) Nitrogen B) Carbon dioxide C) Oxygen D) Carbon monoxide

24. In terrestrial invertebrates like insects, gas exchange occurs through a system of tubes called:

A) Book lungs B) Gills C) Tracheae D) Alveoli

25. Which chamber of the human heart receives oxygenated blood from the lungs?

A) Right atrium B) Right ventricle C) Left atrium D) Left ventricle

26. What is the primary role of the diaphragm during inspiration?

A) It relaxes and moves upward, decreasing thoracic volume B) It contracts and moves downward, increasing thoracic volume C) It remains stationary D) It contracts and moves upward, decreasing thoracic volume

27. The respiratory pigment in the blood of some annelids (like earthworms) is dissolved directly in the plasma and is called:

A) Hemoglobin B) Hemocyanin C) Chlorocruorin D) Myoglobin

28. The process by which air moves into and out of the lungs is known as:

A) Diffusion B) Gas exchange C) Ventilation D) Perfusion

29. Which of the following has the highest affinity for hemoglobin compared to oxygen?

A) Carbon dioxide B) Carbon monoxide C) Nitrogen D) Bicarbonate

30. The structure that connects the larynx to the bronchi is the:

A) Pharynx B) Esophagus C) Trachea D) Bronchioles

31. What is the primary function of the nasal conchae?

A) To produce mucus B) To humidify, warm, and filter inhaled air C) To resonate voice sounds D) To detect odors

32. When the partial pressure of CO2 in the blood increases, what happens to the affinity of hemoglobin for oxygen?

A) It increases B) It decreases C) It remains unchanged D) It fluctuates unpredictably

33. Which group of animals typically uses cutaneous respiration (breathing through the skin)?

A) Mammals B) Birds C) Amphibians D) Reptiles

34. The process of gas exchange between the blood and the body tissues is called:

A) External respiration B) Internal respiration C) Ventilation D) Cellular respiration

35. Hemerythrin is a respiratory pigment found in some marine invertebrates, which contains:

A) Copper B) Iron C) Magnesium D) Manganese

36. The 'chloride shift' is a process associated with the transport of which gas in red blood cells?

A) Oxygen B) Carbon dioxide C) Nitrogen D) Carbon monoxide

37. Which part of the brain contains chemoreceptors that are sensitive to changes in blood CO2 and pH levels?

A) Cerebellum B) Pons C) Medulla oblongata D) Olfactory bulb

38. What is the partial pressure of carbon dioxide (PCO2) in the alveoli?

A) About 100 mmHg B) About 40 mmHg C) About 45 mmHg D) About 0.3 mmHg

39. The vocal cords are located within the:

A) Pharynx B) Nasal cavity C) Larynx D) Trachea

40. In mammals, the primary muscle involved in quiet inspiration is the:

A) External intercostals B) Internal intercostals C) Diaphragm D) Abdominal muscles

41. Which of the following respiratory pigments has the lowest affinity for oxygen?

A) Hemoglobin B) Myoglobin C) Hemocyanin D) Chlorocruorin

42. The exchange of gases between the air in the alveoli and the blood in the pulmonary capillaries is called:

A) Internal respiration B) Cellular respiration C) Pulmonary ventilation D) External respiration

43. What is the approximate percentage of oxygen transported by hemoglobin in the blood?

A) 1.5% B) 98.5% C) 70% D) 30%

44. The structure that prevents food from entering the trachea is the:

A) Uvula B) Epiglottis C) Glottis D) Cricoid cartilage

45. What is the role of the pons in respiratory regulation?

A) It contains the primary chemoreceptors B) It modifies the rate and depth of breathing initiated by the medulla C) It controls voluntary breathing D) It detects changes in lung stretch

46. Which of the following statements about hemoglobin is FALSE?

A) It is a protein found in red blood cells. B) It binds to oxygen reversibly. C) It transports most of the carbon dioxide in the blood. D) It contains four polypeptide chains and four heme groups.

47. The process of exhalation during normal, quiet breathing is primarily:

A) An active process involving muscle contraction B) A passive process due to elastic recoil C) Controlled by the diaphragm alone D) Dependent on external intercostal muscles

48. In which organism is respiration mediated by book lungs?

A) Grasshopper B) Earthworm C) Scorpion D) Fish

49. The partial pressure of oxygen (PO2) in the tissues is typically around:

A) 100 mmHg B) 40 mmHg C) 95 mmHg D) 159 mmHg

50. The main function of the respiratory system is to facilitate:

A) Nutrient absorption B) Waste excretion C) Gas exchange D) Hormone transport

Respiration – structures, pigments, gas transport and regulation - Online Test

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