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

Which of the following pairs of iron complexes and their function in living organisms is not correctly matched?

  1. Catalase - H2O2 metabolism

  2. Ferritin - Plasma Fe transport

  3. Cytochrome c - Electron transport

  4. Hemoglobin - Blood O2 transport

  5. Myoglobin - Muscle O2 storage
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Within cells, iron is stored in a protein complex as ferritin. Ferritin is a intracellular protein that stores iron and releases it in a controlled fashion. Iron circulates in plasma bound to transferrin (which can bind one or two iron molecules).

Multiple choice

Oxygen is an important component of which process?

  1. Respiration

  2. Transpiration

  3. Evaporation

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

Respiration is the process by which living organisms use oxygen to break down glucose and produce energy. Without oxygen, aerobic respiration cannot occur.

Multiple choice

Mountaineers carry oxygen cylinders with them. What is the main reason to do so?

  1. Volume of oxygen increases with the altitude.

  2. Volume of oxygen decreases with the altitude.

  3. Due to the presence of nitrogen on high altitudes

  4. As the air becomes thick at high altitudes, breathing becomes difficult.

  5. Due to the presence of poisonous gases at high altitudes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is the correct option. The volume of oxygen decreases with the rise in altitude. So, mountaineers carry oxygen cylinders.

Multiple choice

Why is oxygen, in its purified form, used in hospitals?

  1. For artificial respiration

  2. For burning of medical waste

  3. Oxygen is used in providing pneumatic pressure in medical equipments.

  4. Decomposition of bodies

  5. To clean medical equipment
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is the correct option. Oxygen in its purified form is used for artificial respiration in hospitals.

Multiple choice

Match the hemoproteins in column I with their function in column II.

 
Column I
Column II
P. Haemoglobin 1. Degradation of hydrogen peroxide
Q. Myoglobin 2. Carrying of oxygen molecules to muscle tissues
R. Cytochromec 3. Transport of oxygen in blood
S. Catalase 4. Involvement in electron transport chain

  1. P - 1; Q - 2; R - 3; S - 4

  2. P - 2; Q - 1; R - 4; S - 3

  3. P - 3; Q - 2; R - 4; S - 1

  4. P - 3; Q - 4; R - 1; S - 2

  5. P - 4; Q - 3; R - 2; S - 1
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The primary function of haemoglobin (Hb) is to transport oxygen in blood. Myoglobin contains a heme (prosthetic) group, which is responsible for its main function (carrying of oxygen molecules to muscle tissues). Cytochrome c is a component of the electron transport chain in mitochondria. Catalase in an enzyme produced by our liver to break down hydrogen peroxide.

Multiple choice

Which of the following compounds is/are inhibitor(s) for oxygen binding to haemoglobin?

P. CO Q. CO2 R. NO

  1. Only P

  2. Only R

  3. Both P and Q

  4. Both Q and R

  5. All of these

Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Correct answer. Besides the oxygen ligand, which binds to haemoglobin in a cooperative manner, haemoglobin ligands also include competitive inhibitors such as carbon monoxide (CO) and allosteric ligands such as carbon dioxide (CO2) and nitric oxide (NO). The carbon dioxide is bound to amino groups of the globin proteins as carbaminohaemoglobin, and is thought to account for about 10% of carbon dioxide transport in mammals. Nitric oxide is bound to specific thiol groups in the globin protein to form an S-nitrosothiol, which dissociates into free nitric oxide and thiol again, as the haemoglobin releases oxygen from its heme site. This nitric oxide transport to peripheral tissues is hypothesised to assist oxygen transport in tissues, by releasing vasodilatory nitric oxide to tissues in which oxygen levels are low.

Multiple choice

In high altitudes the

  1. number of RBC increases

  2. size of RBC increases

  3. number of RBC decreases

  4. size of RBC decreases
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

At high altitudes, the number of RBCs increases.

Multiple choice

CO is transported mainly as

  1. bicarbonates dissolved in plasma

  2. bicarbonates carried by white blood cells

  3. carbonic acid in plasma

  4. carbonic acid in RBC
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice

Oxyhaemoglobin is dissociated into oxygen and deoxyhaemoglobin due to

  1. excess of O2 pressure in tissues

  2. less of O2 pressure in tissues

  3. less of O2 pressure in blood

  4. less of CO2 pressure in blood
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Oxyhaemoglobin dissociates to release oxygen in tissues where oxygen partial pressure is low. This pressure gradient drives oxygen from hemoglobin into tissues. In lungs, high O2 pressure promotes oxygen binding.

Multiple choice

Which among the following statements does NOT characterise cellular respiration?

  1. In the mitochondria of the cells, oxygen is consumed and carbon dioxide is produced.

  2. Blood with haemoglobin is able to transport 26 times more oxygen than plasma without haemoglobin.

  3. Each body cell releases carbon dioxide into nearby capillaries by perfusion.

  4. The body cells uses ATP for all metabolic reactions.

  5. The capillaries are permeable to oxygen.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Each body cell releases carbon dioxide into nearby capillaries by diffusion, because the level of carbon dioxide is higher in the body cells than in the blood. In the capillaries, some of the carbon dioxide is dissolved in plasma and some is taken by the haemoglobin, but most enters the red blood cells where it binds with water to form carbonic acid.

Multiple choice

In human adults, about 5 litres of blood contributes to 7-8% to the body weight. Which among the following statements regarding blood composition is WRONG?

  1. Erythrocytes are the dominant cells in the blood.

  2. Blood platelets perform their functions exclusively in the blood stream.

  3. Erythrocytes contribute about 43% of the total volume of the blood.

  4. Blood cells have epithelial origin.

  5. Leukocytes can leave the blood stream.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Blood is sometimes considered to be a fluid connective tissue because of the mesenchymal origin of its cells and a low ratio of cells to liquid intercellular substance, the blood plasma.

Multiple choice

Oxygen in our blood is transported by a pigment named

  1. hemoglobin

  2. keratin

  3. collugen

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

Hemoglobin is the iron-containing pigment in red blood cells that transports oxygen from the lungs to body tissues and carries carbon dioxide back to the lungs. It gives blood its red color and is essential for respiration.