Biology

Respiration and Gas Transport

647 Questions

Respiration and gas transport deal with the physiological mechanisms of breathing, including the role of hemoglobin in oxygen transport and the removal of carbon dioxide from the blood. Questions cover both aerobic and anaerobic processes, along with related phenomena like altitude sickness. This human biology topic is a staple in the science sections of competitive tests.

Oxygen and hemoglobin transportAnaerobic respiration effectsCarbon dioxide removalAltitude sickness causesBreathing rate regulation

Respiration and Gas Transport Questions

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.

Multiple choice bio-chemistry cell membrane regulation of respiration transport of respiratory gases buffer and its role

When carbon dioxide concentration in blood increases, breathing becomes ............ and ...........

  1. Shallower and slow

  2. Slow and deep

  3. Faster and deeper

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

When the concentration of carbon dioxide increases in blood that results in decreasing the affinity of hemoglobin towards oxygen or amount of oxygen is less in blood. To compensate the oxygen amount breathing goes faster and deeper and is known as hyperventilation which is controlled by the medullary respiratory center.

So the correct option is 'Faster and deeper'.

Multiple choice bio-chemistry cell membrane regulation of respiration transport of respiratory gases buffer and its role

Each $100$ml of human arterial blood carries 'P' ml of $O _2$ and 'Q' ml of $CO _2$ whereas each $100$ml of venous blood carries 'R' ml of $O _2$ and 'S' ml of $CO _2$. Choose the correct values of P, Q, R and S.

  1. P-$48$ml, Q-$19$ to $20$ml, R-$52$ml, S-$14$ to $15$ml
  2. P-$19$ to $20$ml, Q-$48$ml, R-$14$ to $15$ml, S-$52$ml
  3. P-$14$ to $15$ml, Q-$52$ml, R-$19$ml to $20$ml, S-$48$ml
  4. P-$52$ml, Q-$14$ to $15$ml, R-$48$ml, S-$19$ to $20$ml
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Arterial blood carries approximately 19-20 ml of O2 and 48 ml of CO2 per 100 ml, while venous blood carries about 14-15 ml of O2 and 52 ml of CO2.

Multiple choice bio-chemistry cell membrane regulation of respiration transport of respiratory gases buffer and its role

What is $pO _2$ and $pCO _2$ in synthematic arteries?

  1. $pO _2$ $40$mm Hg, $pCO _2$ $45$mm Hg
  2. $pO _2$ $95$mm Hg, $pCO _2$ $104$mm Hg
  3. $pO _2$ $95$mm Hg, $pCO _2$ $40$mm Hg
  4. $pO _2$ $45$mm Hg, $pCO _2$ $40$mm Hg
  5. $pO _2$ $104$mm Hg, $pCO _2$ $159$mm Hg
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In systemic arteries, the partial pressure of oxygen (pO2) is approximately 95 mm Hg, and the partial pressure of carbon dioxide (pCO2) is approximately 40 mm Hg.

Multiple choice bio-chemistry cell membrane regulation of respiration transport of respiratory gases buffer and its role

Rate of breathing is controlled mainly by ________________.

  1. $CO _{2}$ level in blood

  2. pH in blood
  3. $O _{2}$ level in blood
  4. $O _{2}$ level and pH in blood.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Rate of breathing is mainly controlled by $CO _2$ level in the blood. Excess $CO _2$ decrease the pH of the blood and it mainly stimulate the respiratory centre of the brain (i.e., Medulla oblongata) and increase the inspiratory and expiratory signals to the respiratory muscles.

Multiple choice bio-chemistry cell membrane regulation of respiration transport of respiratory gases buffer and its role

Rate of breathing is controlled mainly by

  1. $CO _2$ level in blood

  2. pH in blood
  3. $O _2$ level in blood
  4. $O _2$ level and pH in blood
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The rate of breathing is controlled mainly by CO$ _2$ level in blood. The partial pressure of carbon dioxide (PCO$ _2$) controls the respiratory rate. The respiratory centre measures the levels of carbon dioxide, oxygen and acidosis in the arterial blood and sends message accordingly. If the carbon dioxide levels in the blood increases, the rate and depth of breathing increases.

Thus, the correct answer is 'CO$ _2$ level in blood.'

Multiple choice bio-chemistry cell membrane regulation of respiration transport of respiratory gases buffer and its role

Which of the following is not a stimulus for breathing?

  1. Rising $CO _2$ levels

  2. Rising blood pressure
  3. Arterial $pO _2$ below $60$mm of Hg

  4. Change in pH of arterial blood
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

An increased concentration of carbon dioxide is the strongest stimulus to breathe more deeply and more frequently. When the carbon dioxide concentration in the blood is low, the brain decreases the frequency and depth of breath.

So the correct answer is 'Rising CO2 levels'.

Multiple choice bio-chemistry cell membrane regulation of respiration transport of respiratory gases buffer and its role

Central chemoreceptors are sensitive to the

  1. pH of their environment

  2. Level of oxygen

  3. High blood pressure

  4. Level of sugar in blood
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Central chemoreceptors are located on the ventrolateral medullary surface in the central nervous system. There receptors act to detect the changes in pH of their environment by detecting alteration in the concentration of O$ _2$ and CO$ _2$ of nearby cerebrospinal fluid. The decrease in CO$ _2$ causes the blood to become more acidic while it's increase makes the blood alkaline.
So, the correct answer is 'pH of their environment'.
Multiple choice biology animal tissue muscular tissues muscle tissue muscle tissues

Each myoglobin binds with ________________.

  1. One molecule of $O _2$
  2. $4$ molecule of $O _2$
  3. Two molecules of $O _2$
  4. $3$ molecules of $O _2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Myoglobin is similar to hemoglobin in a way that both are oxygen-carrying protein but in a different location. It can bind to only one molecule of oxygen because it is a monomeric protein.

So the correct option is "One molecule of $O _2$".

Multiple choice bio-chemistry transportation in plants and circulation in animals role of blood in transport function of blood blood and lymph

Most carbon dioxide in blood is in the form of

  1. carbon dioxide

  2. carbonic acid

  3. carbon monoxide

  4. hydrogencarbonate
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Carbon dioxide is transported in the blood from the tissue to the lungs in three ways: (i) dissolved in solution; (ii) buffered with bicarbonate and (iii) bound to proteins, particularly haemoglobin. Majority of the carbon dioxide in the blood is carried by means of a bicarbonate buffer system. So, the correct option is 'hydrogen carbonate'.