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

Rising carbon dioxide levels in blood

High nitrogen levels

Low heart rate

Low oxygen levels in muscles

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

Nose → Larynx → Trachea → Bronchi → Alveoli

Mouth → Bronchi → Larynx → Trachea → Alveoli

Nose → Bronchi → Trachea → Alveoli

Nose → Trachea → Larynx → Bronchi → Alveoli

3. What is the function of the bronchioles?

Produce mucus

Filter blood

Exchange gases

Transport air to alveoli

4. What happens when alveolar walls break down?

Reduced surface area for gas exchange

Better lung capacity

Faster breathing

Improved oxygen absorption

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

Pneumonia

Bronchitis

Asthma

Emphysema

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

Digestion

Excretion

Photosynthesis

Cellular respiration

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

Weakened diaphragm

Less physical activity

High carbon dioxide levels in blood

Damaged alveoli and reduced surface area

8. How does smoking affect lung alveoli?

Increases their number

Strengthens their walls

Cleans them

Destroys them over time

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

Vital capacity

Tidal volume

Residual volume

Inspiratory reserve volume

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

Larynx

Trachea

Bronchi

Pharynx

11. Which organ is directly responsible for breathing?

Heart

Kidney

Lungs

Liver

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

It has no relation to smoking

It often begins in the bronchi

It is caused by bacteria

It cannot be detected early

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

Higher red blood cell count

Stronger heart

Frequent use of inhalers

Improved ventilation and alveolar efficiency

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

Typhoid

Lung cancer

Tuberculosis

Hepatitis

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

Larynx

Bronchi

Nose

Trachea

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

Paralyzes or destroys them

Increases their activity

Strengthens their movement

Has no effect

17. What is the medical term for breathing?

Respiration

Ventilation

Circulation

Inhalation

18. What is the role of hemoglobin in respiration?

Filters oxygen

Transports oxygen in the blood

Produces enzymes

Traps bacteria

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

Oxygen

Carbon dioxide

Methane

Nitrogen

20. Which part of the brain controls breathing?

Cerebrum

Hypothalamus

Medulla oblongata

Cerebellum

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

Bronchi

Alveoli

Trachea

Pleura

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

It improves immunity

It increases cilia movement

It impairs immune cells and damages mucosal barriers

It raises oxygen levels

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

Damaged cilia and excess mucus

Low immunity

Lung expansion

Infection

24. What is the main function of the trachea?

Trap carbon dioxide

Site of gas exchange

Filter and moisten air

Transport air to bronchi

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

Water vapor

Carbon monoxide

Oxygen

Nicotine

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

Decreases below atmospheric pressure

Increases above atmospheric pressure

Matches atmospheric pressure

Stays constant

27. Which process moves oxygen from lungs to blood?

Osmosis

Filtration

Active transport

Diffusion

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

Traps dust and microbes

Breaks down food

Increases oxygen

Lubricates the lungs

29. What structure branches into bronchi?

Nose

Larynx

Trachea

Pharynx

30. What happens to the chest cavity during exhalation?

Contracts and volume decreases

Expands more

Becomes larger

Remains unchanged

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

Regulate temperature

Filter blood

Exchange gases

Produce energy

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

Digestive system

Circulatory system

Nervous system

Excretory system

33. Which of the following best describes exhalation?

Sudden air intake

Absorption of oxygen

Passive process involving muscle relaxation

Active contraction of diaphragm

34. Which structure prevents food from entering the trachea?

Larynx

Epiglottis

Alveolus

Pharynx

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

Bronchi

Alveoli

Trachea

Bronchioles

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

Enhances oxygen binding

Dissolves in plasma

Binds with hemoglobin, reducing oxygen transport

Destroys red blood cells

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

Asthma

Arthritis

Diabetes

Lung cancer

38. What surrounds the alveoli to facilitate gas exchange?

Veins

Capillaries

Arteries

Bronchioles

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

Carbon dioxide

Hydrogen

Nitrogen

Oxygen

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

Trachea

Pharynx

Nasal cavity

Larynx

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

Pharynx

Alveoli

Trachea

Nasal cavity

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

Stomach acid

Kidney function

Bile

Cilia and mucus in the airways

43. How does smoking contribute to chronic bronchitis?

Reduces blood flow

Strengthens immune system

Irritates bronchi and causes long-term inflammation

Increases lung elasticity

44. Which muscle is primarily responsible for breathing?

Diaphragm

Pectoral muscle

Abdominal muscle

Intercostal muscle

45. What is tidal volume?

Maximum air that can be exhaled

Air exchanged in a normal breath

Air remaining after exhalation

Volume of oxygen in blood

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

Bronchus

Nasal cavity

Pharynx

Trachea

47. During inhalation, what happens to the diaphragm?

Expands sideways

Contracts and moves upward

Contracts and moves downward

Relaxes and moves upward

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

Respiration

Exhalation

Ventilation

Inhalation

49. What is the function of intercostal muscles?

Filter air

Help in heart contractions

Move ribs during breathing

Produce mucus

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

Skin rash

Joint pain

Chronic cough

High blood sugar

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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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