Biology

Respiration and Gas Transport

606 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

The most stable product formed with haemoglobin is

  1. CO2

  2. O2

  3. CO

  4. SO2
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Carbon monoxide (CO) binds to haemoglobin with approximately 200-250 times greater affinity than oxygen, forming carboxyhaemoglobin. This stable complex is the strongest bond among the options, which is why CO is so toxic.

Multiple choice

The process of respiration is concerned with

  1. Intake of O2

  2. Liberation of O2

  3. Liberation of CO2

  4. Liberation of energy
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Respiration is fundamentally about energy liberation - the process where cells use oxygen to break down glucose and release ATP energy. While oxygen intake and CO2 release occur during respiration, they are means to the end of energy production. Options A, B, and C describe only parts of the process.

Multiple choice

Blood possesses CO2 In the form

  1. NaHCO3

  2. H2C O3

  3. HbCO2

  4. HbCO2 & HbCO
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

CO2 is transported in blood as carbaminohemoglobin (HbCO2) when bound to hemoglobin's amino groups. This accounts for about 20-30% of CO2 transport. NaHCO3 (sodium bicarbonate) is the main transport form (70%), H2CO3 is carbonic acid (transient), and HbCO is carbon monoxide bound to hemoglobin (a toxin, not normal CO2 transport).

Multiple choice

Carbon monoxide, a highly poisonous gas, reacts with blood to form

  1. oxy-haemoglobin

  2. carboxyhaemoglobin

  3. nitro-haemoglobin

  4. carbon dioxide haemoglobin
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Carbon monoxide binds to hemoglobin in red blood cells to form carboxyhaemoglobin, which is extremely stable (200+ times stronger bond than oxyhemoglobin). This prevents oxygen transport, causing CO poisoning. CO does not form nitro-haemoglobin, carbon dioxide haemoglobin, or oxy-haemoglobin.

Multiple choice

Which of the following is a false statement?

  1. People living at high altitude have greater red blood cell concentration.

  2. The maximum haemoglobin concentration is 34 g in 100 ml red blood cells.

  3. The number of haemoglobin in one red blood cell is 28 to 30.

  4. Red blood cells contain large quantity of carbonic anhydrage enzyme.

  5. Red blood cell has convex disc-like structure.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

False statement

Multiple choice

Erythropoesis is decreased in/at

  1. hypoxia

  2. anaemia

  3. high altitudes

  4. heavy exercise

  5. complete bed rest
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

During complete bed rest, rate of red blood cell production decreases.

Multiple choice

Identify the false statement.

  1. Life span of a red blood cell is 120 days.

  2. Red blood cell have no mitochondria.

  3. Daily loss of iron is 6 g/day.

  4. Iron is absorbed by small intestine.

  5. Iron is stored in form of haemosiderin.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Wrong statement

Multiple choice

Which of the following statements is/are false? a. RBCs are red coloured due to the presence of haemoglobin. b. Haemoglobin is a carrier of carbon dioxide. c. Whenever there is a blood flow due to an injury, the platelets help in the clotting of blood.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only a and c

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

Haemoglobin is a carrier of carbon dioxide, is a wrong statement. Haemoglobin is the carrier of oxygen. Hence, this is the correct option.

Multiple choice

Which pigment helps in the transportation of oxygen in humans?

  1. Leghaemoglobin

  2. Haemoerythrin

  3. Haemoglobin

  4. Haemolysin
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Transportation of oxygen in humans is carried out by haemoglobin, which is stored in RBC’s. Haemoerythrin pigment is present in lower organisms while leghaemoglobin is present inside the root nodules of leguminous plants, e.g. pulses. Haemolysin is not a pigment. Thus, option (3) is correct.