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

Which of the following statements is/are false?

a. Haemoglobin is present in the RBCs as a red-coloured iron-containing pigment. b. Oxygen plays quite a insignificant role in the regulation of respiratory rhythm. c. Vital capacity is the total volume of air accommodated in the lungs at the end of a forced inspiration.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is the correct option as this statement is false. Total lung capacity is the total volume of air accommodated in the lungs at the end of a forced inspiration.

Multiple choice

What is the effect of H2S on blood?

  1. It destroys the nucleus of the blood cells.

  2. It destroys the haemoglobin in the blood.

  3. It destroys the plasma membrane of the blood cells.

  4. It reacts with haemoglobin and forms sulphoxy haemoglobin.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

H2S destroys the haemoglobin in the blood.

Multiple choice

What is supposed to happen, if a person stays on Mount Everest for some days?

  1. Production of red blood cells will decrease in his body.

  2. Production of red blood cells will increase in his body.

  3. Number of red blood cells will not change.

  4. Size of his red blood cells will increase.

  5. Size of his red blood cells will decrease.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Due to great height one respires thin air, getting lesser amounts of oxygen. That is why production of red blood cells increases to increase the amount of hemoglobin present in the cells.

Multiple choice

Which one of the following statements is correct?

  1. All animals require a medium for cellular respiration.

  2. In all the animals, oxygen is transported by haemoglobin of the blood.

  3. All animals take oxygen from water or air through gills or lungs only.

  4. All animals need oxygen for respiration.

  5. Alveoli of lungs have columnar epithelium.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Exchange of gases requires a definite medium. For eg.,  in mammals exchange of gases takes place in alveoli of lungs.

Multiple choice

When man inhales air containing normal concentration of oxygen mixed with carbon monoxide, he feels suffocated because __________.

  1. carbon monoxide reacts with oxygen reducing percentage of oxygen in the air

  2. hemoglobin combines with carbon monoxide and the product cannot dissociate

  3. carbon monoxide affects the nerves of the lungs

  4. carbon monoxide affects the movement of diaphragm

  5. carbon monoxide affects the intercostal muscles
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In comparison to oxygen ,carbon monoxide combines more readily with hemoglobin (about 250 times more) and thus person suffers from suffocation due to lack of oxygen.

Multiple choice

In which form is carbon dioxide mainly carried in the blood?

  1. Bicarbonate ions

  2. Carbaminohemoglobin

  3. In dissolved state

  4. Carbonic acid

  5. Sodium carbonate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

About 70% of the carbon dioxide is transferred in this way. Bicarbonate ions are formed by the dissociation of carbonic acid which is formed by the union of carbon dioxide and water in the presence of carbonic anhydrase enzyme.

Multiple choice

Which gas inhibits the blood's ability to carry oxygen to vital organs?

  1. Carbon dioxide

  2. Carbon monoxide

  3. Nitric oxide

  4. Ammonia

  5. Methane
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Carbon monoxide inhibits the blood's ability to carry oxygen to body tissues including vital organs such as heart and brain. When CO is inhaled, it combines with the oxygen carrying haemoglobin of the blood to form carboxyhaemoglobin (COHb). Once combined with the haemoglobin, the haemoglobin is no longer available for transporting oxygen.  

Multiple choice

Which of the following signifies the oxygen transport by fetal blood?

  1. In a developing embryo, the blood bouncing back to the umbilical vein is completely saturated with O2.

  2. Fetal hemoglobin has a higher compatibility for oxygen than adult hemoglobin.

  3. In a normal foetus, the blood has a lower hemoglobin content than adult blood.

  4. Blood reaching the brain of a fetus has the same PO2 as that of blood in the descending aorta.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is the correct answer. Fetal blood has a higher hemoglobin content than adult blood and fetal hemoglobin has a higher affinity for O2 than adult hemoglobin. Therefore, O2 content of blood in the umbilical vein is about 160 ml/l.

Multiple choice

Which of the following statements referring to transport of the gases by the blood is correct?

  1. Exiting from the lungs, each litre of blood carries about 2 ml of oxygen.

  2. Haemoglobin is half saturated with oxygen when the PO2 is about 3.3 kPa and PCO2 is 5.3 kPa.

  3. As the PCO2 rises, the compatibility of hemoglobin for oxygen increases.

  4. Each litre of arterial blood contains about 5 mL of carbon dioxide.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The primary function of hemoglobin is to transport oxygen. When half of the sites are filled with oxygen, the blood is said to be 50% saturated. This happens when the PO2 is about 3.3 kPa and PCO2 is 5.3 kPa.