Biology Respiration Online Mcqs Test

Mustansar KhanLast Updated: October 14, 2025

Important Biology Respiration Question and Answer

Total Questions:	50
Time Allowed:	25 Minutes
Total Marks:	50
How to Attempt Test:	Please choose the right Option in MCQ-type question.
Test Helpful For:	Biology Test MDCAT Test FPSC/PPSC/SPSC/KPPSC/BPSC/AJKPSC/NTS Biology Interview Question Answer Universities Entrance Test

Biology Respiration Practice Test Online With Explanation

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1. Which of the following respiratory structures is shared with the digestive system?

Trachea

Bronchus

Nasal cavity

Pharynx

2. Which condition is commonly caused by long-term smoking?

Arthritis

Asthma

Diabetes

Lung cancer

3. What happens to the chest cavity during exhalation?

Expands more

Contracts and volume decreases

Remains unchanged

Becomes larger

4. Which structure prevents food from entering the trachea?

Alveolus

Pharynx

Epiglottis

Larynx

5. Which process moves oxygen from lungs to blood?

Diffusion

Active transport

Osmosis

Filtration

6. Which muscle is primarily responsible for breathing?

Abdominal muscle

Pectoral muscle

Diaphragm

Intercostal muscle

7. What is the term for the movement of air into and out of the lungs?

Exhalation

Inhalation

Ventilation

Respiration

8. What happens to the air pressure in lungs during inhalation?

Decreases below atmospheric pressure

Increases above atmospheric pressure

Matches atmospheric pressure

Stays constant

9. What is tidal volume?

Maximum air that can be exhaled

Volume of oxygen in blood

Air remaining after exhalation

Air exchanged in a normal breath

10. What happens when alveolar walls break down?

Reduced surface area for gas exchange

Faster breathing

Improved oxygen absorption

Better lung capacity

11. Which gas diffuses from the alveoli into the blood?

Methane

Carbon dioxide

Oxygen

Nitrogen

12. Which of the following helps protect the lungs from harmful substances in the air?

Bile

Kidney function

Stomach acid

Cilia and mucus in the airways

13. Which organ system works closely with the respiratory system for gas transport?

Digestive system

Excretory system

Nervous system

Circulatory system

14. Which respiratory disease involves inflammation and narrowing of airways?

Bronchitis

Asthma

Pneumonia

Emphysema

15. Which of the following best describes exhalation?

Active contraction of diaphragm

Sudden air intake

Passive process involving muscle relaxation

Absorption of oxygen

16. Which of the following is a major component of cigarette smoke that damages lung tissue?

Carbon monoxide

Water vapor

Oxygen

Nicotine

17. What is the role of mucus in the respiratory tract?

Lubricates the lungs

Increases oxygen

Breaks down food

Traps dust and microbes

18. Which term refers to the maximum amount of air exhaled after a deep breath?

Vital capacity

Inspiratory reserve volume

Residual volume

Tidal volume

19. Which part of the brain controls breathing?

Medulla oblongata

Cerebellum

Cerebrum

Hypothalamus

20. How does smoking contribute to chronic bronchitis?

Reduces blood flow

Strengthens immune system

Irritates bronchi and causes long-term inflammation

Increases lung elasticity

21. What is the function of intercostal muscles?

Help in heart contractions

Produce mucus

Filter air

Move ribs during breathing

22. What is the main cause of reduced oxygen uptake in smokers?

High carbon dioxide levels in blood

Weakened diaphragm

Less physical activity

Damaged alveoli and reduced surface area

23. What is the correct sequence of airflow during inhalation?

Nose → Bronchi → Trachea → Alveoli

Nose → Trachea → Larynx → Bronchi → Alveoli

Mouth → Bronchi → Larynx → Trachea → Alveoli

Nose → Larynx → Trachea → Bronchi → Alveoli

24. Which part of the lungs are damaged in emphysema?

Pleura

Alveoli

Trachea

Bronchi

25. Which of the following is an early symptom of lung damage due to smoking?

Joint pain

Skin rash

Chronic cough

High blood sugar

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26. How does the body primarily detect the need to breathe faster?

Low oxygen levels in muscles

High nitrogen levels

Low heart rate

Rising carbon dioxide levels in blood

27. What is the primary function of the respiratory system?

Produce energy

Filter blood

Regulate temperature

Exchange gases

28. Which gas is transported from the blood to the alveoli to be exhaled?

Hydrogen

Oxygen

Carbon dioxide

Nitrogen

29. How does chronic smoking increase the risk of infections?

It increases cilia movement

It improves immunity

It impairs immune cells and damages mucosal barriers

It raises oxygen levels

30. How does smoking affect lung alveoli?

Destroys them over time

Strengthens their walls

Increases their number

Cleans them

31. Which process uses oxygen to produce energy in body cells?

Photosynthesis

Cellular respiration

Excretion

Digestion

32. What part of the respiratory system divides into left and right branches?

Nasal cavity

Trachea

Larynx

Pharynx

33. What effect does smoking have on cilia in the respiratory tract?

Paralyzes or destroys them

Increases their activity

Strengthens their movement

Has no effect

34. What is the role of hemoglobin in respiration?

Filters oxygen

Transports oxygen in the blood

Produces enzymes

Traps bacteria

35. Which disease is strongly linked to both active and passive smoking?

Lung cancer

Typhoid

Tuberculosis

Hepatitis

36. What structure branches into bronchi?

Pharynx

Trachea

Larynx

Nose

37. What is the main function of the trachea?

Site of gas exchange

Trap carbon dioxide

Transport air to bronchi

Filter and moisten air

38. Which part of the respiratory system acts as a resonating chamber for voice?

Trachea

Pharynx

Alveoli

Nasal cavity

39. What is the main reason for coughing in smokers?

Low immunity

Lung expansion

Infection

Damaged cilia and excess mucus

40. Which structure warms, moistens, and filters the air we breathe?

Larynx

Trachea

Nose

Bronchi

41. What surrounds the alveoli to facilitate gas exchange?

Bronchioles

Arteries

Capillaries

Veins

42. Which of the following structures is the main site of gas exchange in the lungs?

Bronchioles

Bronchi

Trachea

Alveoli

43. Which of the following best explains why athletes often have better lung capacity?

Frequent use of inhalers

Higher red blood cell count

Stronger heart

Improved ventilation and alveolar efficiency

44. Which of the following is true about lung cancer?

It often begins in the bronchi

It has no relation to smoking

It cannot be detected early

It is caused by bacteria

45. During inhalation, what happens to the diaphragm?

Contracts and moves downward

Expands sideways

Relaxes and moves upward

Contracts and moves upward

46. What is the function of the bronchioles?

Filter blood

Transport air to alveoli

Produce mucus

Exchange gases

47. Which organ is directly responsible for breathing?

Lungs

Liver

Kidney

Heart

48. Which part of the respiratory system contains vocal cords?

Larynx

Pharynx

Trachea

Bronchi

49. How does carbon monoxide from cigarette smoke affect oxygen transport?

Destroys red blood cells

Enhances oxygen binding

Binds with hemoglobin, reducing oxygen transport

Dissolves in plasma

50. What is the medical term for breathing?

Circulation

Inhalation

Respiration

Ventilation

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Mustansar KhanLast Updated: October 14, 2025

Important Biology Respiration Question and Answer

Biology Respiration Practice Test Online With Explanation

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