Free Respiration MCQs with Answers

446 Respiration MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.

The human respiratory system includes the air passages, lungs, alveoli and breathing muscles, while gaseous exchange explains how oxygen enters blood and carbon dioxide leaves it by diffusion. The effects of smoking include damage to cilia and alveoli, reduced gas exchange, chronic bronchitis, emphysema and increased risk of lung cancer.

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446 questions · page 9 of 23

  • A. Osmosis
  • B. Photosynthesis
  • C. Translocation
  • D. Transpiration
  • E. Transcription

Explanation: Water is lost by the process of transpiration, the process of water movement through a plant, and its evaporation from aerial parts, such…

Correct answer: Transpiration
  • A. X only
  • B. X and Y only
  • C. X and Z only
  • D. Y and Z only
  • E. X, Y and Z

Explanation: During breathing diaphragm contracts and external intercostal muscles contract, which are labeled as Z and Y respectively in the above…

Correct answer: Y and Z only
  • A. Option A
  • B. Option B
  • C. Option C
  • D. Option D
  • E. Option E

Explanation: During inspiration, contraction of the diaphragm causes its dome shape to flatten its dome shape whereas the contraction of the external…

Correct answer: Option E
  • A. Clam warm
  • B. Spider
  • C. Silverfish
  • D. Leech

Explanation: Book lungs are respiratory organs found in certain arthropods, specifically spiders and some related arachnids.

Correct answer: Spider
  • A. More rate of respiration
  • B. Less the rate of respiration
  • C. Rate of respiration has nothing to do with the size of animal
  • D. None of these

Explanation: Larger the organism, more is the distance covered for circulation of blood inside the body...so, more time is taken to circulate blood to…

Correct answer: More rate of respiration
  • A. Decreases the heart rate
  • B. Decreases the blood pressure
  • C. Block the transport or oxygen
  • D. Paralyzes cells

Explanation: Nicotine causes your blood vessels to constrict or narrow, which limits the amount of blood that flows to your organs.

Correct answer: Block the transport or oxygen
  • A. Larynx
  • B. Trachea
  • C. Bronchi
  • D. Alveoli

Explanation: The gaseous exchange in the human respiratory system takes place between the alveoli and capillaries of the lungs.

Correct answer: Alveoli
  • A. Nitrogen
  • B. Iron
  • C. Carbon
  • D. Hydrogen

Explanation: Iron associated with the heme binds oxygen.

Correct answer: Iron
  • A. Sodium bicarbonate
  • B. Potassium bicarbonate
  • C. Carbamino-haemoglobin
  • D. Dissolved gas in plasma

Explanation: Nearly 20-25 percent of CO2 is transported by RBCs whereas 70 percent of it is carried as bicarbonate.

Correct answer: Sodium bicarbonate
  • A. Stomata
  • B. Mesophyll
  • C. Endoderm
  • D. Xylem

Explanation: The exchange of oxygen and carbon dioxide in the leaf (as well as the loss of water vapor in transpiration) occurs through pores called…

Correct answer: Stomata
  • A. Bronchi
  • B. Bronchiole
  • C. Alveoli
  • D. Trachea

Explanation: Smoking destroys the tiny air sacs, or alveoli, in the lungs that allow oxygen exchange.

Correct answer: Alveoli
  • A. Pleura
  • B. Rib cage
  • C. Pericardium
  • D. Diaphragm

Explanation: Option A: The pleura is a thin layer of tissue that lines the lungs and the chest cavity.

Correct answer: Diaphragm
  • A. In the form of bicarbonate ions.
  • B. Bound to albumin compounds.
  • C. Dissolved in the plasma.
  • D. By the leukocytes.
  • E. Bound to hemoglobin.

Explanation: Bicarbonate ions are involved in the transport of carbon dioxide in the blood.

Correct answer: Bound to hemoglobin.
  • A. Globin
  • B. Glycogen
  • C. Myoglycogen
  • D. Myoglobin

Explanation: Myoglobin is a low molecular weight oxygen-binding heme protein that is found exclusively in the heart and skeletal muscle cells.

Correct answer: Myoglobin
  • A. Tracheal cells
  • B. Goblet cells
  • C. Surfactant cells
  • D. Pleural cells

Explanation: The primary function of goblet cells is to synthesize and secrete mucus.

Correct answer: Goblet cells
  • A. Less than 100
  • B. 10,000
  • C. One million
  • D. None of the above

Explanation: Number of stomata depend on environmental factors like carbon dioxide concentration.

Correct answer: 10,000
  • A. 10
  • B. 20
  • C. 30
  • D. 40

Explanation: In 100 ml of blood, there is about 15 g of Hb, so that 100 ml of blood has the capacity to bind 20.1 ml of oxygen.

Correct answer: 20
  • A. Tuberculosis
  • B. Asthma
  • C. Emphysema
  • D. Bronchitis

Explanation: Option A, tuberculosis, is a bacterial infection of the lungs, characterized by persistent cough, fever, and weight loss.

Correct answer: Emphysema
  • A. Help them float on water
  • B. Limit water loss, by increasing the surface area
  • C. Help them survive in salty environment
  • D. Limit water loss, by reducing the surface area

Explanation: Xerophytes are plants that are adapted to survive in environments, with very little water.

Correct answer: Limit water loss, by reducing the surface area
  • A. Bronchi
  • B. Bronchioles
  • C. Windpipe
  • D. Alveolar duct

Explanation: Another name of the trachea is the 'windpipe'.

Correct answer: Windpipe