Tag: exchange of gases

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Questions Related to exchange of gases

Multiple choice biology the respiratory system factors affecting breathing exchange of gases transport of respiratory gases

A child was killed through asphyxiation. Postmortem confirmed it because a piece of lung put in water.

  1. Settled down

  2. Kept floating

  3. Had blood spots

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In a postmortem, a piece of lung from a child who breathed air will float because of the residual air in the alveoli. If the child never breathed, the lung tissue is dense and will sink.

Multiple choice biology the respiratory system factors affecting breathing exchange of gases transport of respiratory gases

Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?

  1. Quick diffusion cannot occur in so much cells at a time.

  2. All cells are not in contact of the atmosphere.

  3. Air containing intercellular spaces are absent.

  4. All of the above.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Every living cell requires oxygen for performing cellular respiration. In unicellular organisms (e.g amoeba), the single cell is in direct contact with environment. Oxygen passes into it through diffusion. In simple multicellular organisms (e.g, hydra), every cell may take also oxygen through diffusion from environment. This is not possible in multicellular organisms like humans. The body is covered by dead cells. The living cells are not in contact with the external environment. Air containing intercellular spaces are absent. Therefore, quick diffusion cannot occur. Cell to cell diffusion is a very slow process. Passage of oxygen from lungs to toes through cell to cell diffusion will take about three years. Therefore, diffusion cannot meet the oxygen requirements of multicellular organisms like humans.

Therefore, the correct answer is option D.

Multiple choice biology the respiratory system factors affecting breathing exchange of gases transport of respiratory gases

Asphyxia occurs due to 

  1. Rise in level of ${CO _2}$
  2. Fall in level of ${CO _2}$
  3. Rise of ${O _2}$ level
  4. Fall in ${O _2}$ level
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Asphyxia is a condition of severely deficient supply of oxygen to the body that arises from abnormal breathing. Asphyxia causes generalized hypoxia, which affects primarily the tissues and organs. There are many circumstances that can induce asphyxia, all of which are characterized by an inability of an individual to acquire sufficient oxygen through breathing for an extended period of time.

Multiple choice biology the respiratory system factors affecting breathing exchange of gases transport of respiratory gases

Diffusion is insufficient to meet .......... requirement of multicellular organisms like humans.

  1. Oxygen

  2. Carbon dioxide

  3. Nitrogen

  4. Water
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Multicellular organisms need oxygen to live. The multiple layer of cells in multicellular organism means that the surface area to volume ratio is low; so, diffusion happens slowly. If only diffusion would have been the source then only the outer layer of the body would get oxygen and the inner layers would be oxygen deprived.  So, the organism will die.