Tag: biology

Questions Related to biology

High percentage of $CO _2$ and very low percentage of $O _2$ may make a person unconscious due to.

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

  1. Eupnoea

  2. Emphysema

  3. Suffocation

  4. Asphyxia

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Correct Option: D

Read the statements carefully and choose the option representing true statements.
(a) $pO _2$ in the atmospheric air does not change with altiude
(b) Most people who live at high altitude develop polycythemia due to hypoxia
(c) Excess inflation to the lungs is prevented by Hering-Breuer's reflex
(d) While transporting $CO _2$ in blood, blood does not become acidic due to presence of blood buffers.

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

  1. (a) & (c) only

  2. (b) & (c) only

  3. (a), (b) & (c) only

  4. (b), (c) & (d) only

Show answer
Correct Option: D
Explanation:

$pO _2$ of atmospheric air decreases with increasing altitude.

Most people living at high altitude develop polycythemia due to hypoxia as oxygen levels are low.
Hering Breuer's reflex prevent excessive inflation of lungs .
Blood has an efficient buffer system which resists the change in pH even after dissolution of carbon dioxide.
So the correct answer is '(b), (c) & (d) only '.

State whether the following statements are true or false.
The condition in which the body suffers from acute oxygen shortage is called hypoxia.

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

  1. True

  2. False

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Correct Option: A
Explanation:

Hypoxia is a condition in which the body or a region of the body is deprived of oxygen due to the lack of oxygen supply at the tissue level. It is, therefore, the condition in which the body suffers from acute oxygen shortage. So, the correct option is 'True'.

When the blood contains a high percentage of $CO _2$ and a very low percentage of $O _2$ the breathing stops and the person becomes unconscious. This condition is known as.

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

  1. Suffocation

  2. Asphyxia

  3. Emphysema

  4. Eupnea

Show answer
Correct Option: B
Explanation:

Asphyxia is the extreme condition caused by lack of oxygen and excess of carbon dioxide in the blood, produced by interference with respiration or insufficient oxygen in the air; suffocation. Asphyxia is caused by an injury or obstruction of airway passages. So, the correct answer is option B.

When oxygen supply to tissues is inadequate, the condition is?

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

  1. Dyspnoea

  2. Asphyxia

  3. Hypoxia

  4. Apnoea

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Correct Option: C

What is usually present at the time of asphyxiation?

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

  1. Oxyhaemoglobin

  2. Methaemoglobin

  3. Carbaminohaemoglobin

  4. Haemoglobin without oxygen

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Correct Option: D

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

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

  1. Settled down

  2. Kept floating

  3. Had blood spots

  4. None of the above

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Correct Option: B

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

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

  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.

Show answer
Correct Option: D
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.

Asphyxia occurs due to 

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

  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

Show answer
Correct Option: D
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.

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

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

  1. Oxygen

  2. Carbon dioxide

  3. Nitrogen

  4. Water

Show answer
Correct Option: A
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.