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

Consider the following statements:

  1. Helium is used for respiration in deep water instead of nitrogen because it mixes lesser in blood than nitrogen.
  2. Hemoglobin has higher affinity for oxygen than for carbon monoxide.
  3. Helium gas is filled in chips packets to make them fresh for a long time.

Which of the given statements is/are incorrect?

  1. Only 1

  2. Only 2

  3. Only 1 and 3

  4. Only 2 and 3
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

(i) Statement (1) is correct. For respiration by deep sea divers, helium-oxygen mixture is used in preference to nitrogen-oxygen mixture. It is much less soluble in blood than nitrogen. This prevents bends, i.e. the pain caused by formation of nitrogen bubbles in blood veins, when a diver comes to surface. (ii) Statement (2) is wrong. Hemoglobin has higher affinity for carbon monoxide than for oxygen. (iii) Statement (3) is wrong. Nitrogen gas is filled in the chips packets to make them fresh for a long time.

Multiple choice

According to which hypothesis are discontinuous gas exchange cycles an adaptation to reduce the amount of O2 delivered to tissues under low metabolic rate?

  1. Strolling arthropods hypothesis

  2. Oxidative damage hypothesis

  3. Chthonic hypothesis

  4. Hygric hypothesis
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The oxidative damage hypothesis states that discontinuous gas exchange cycles are an adaptation to reduce the amount of O2 delivered to tissues under periods of low metabolic rate.

Multiple choice

Which among the following statements does not characterises cellular respiration?

  1. The capillaries are permeable to oxygen.

  2. The body cells use ATP for all metabolic reactions.

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

  4. Blood with hemoglobin is able to transport 26 times more oxygen than plasma without hemoglobin.

  5. In the mitochondria of the cells, oxygen is consumed and carbon dioxide is produced.
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 hemoglobin, but most enters the red blood cells where it binds with water to form carbonic acid.

Multiple choice

In living organisms, gases like oxygen and carbon dioxide cross the plasma membrane mainly by

  1. passive diffusion through the lipid bilayer

  2. primary active transport

  3. specific gas transport proteins known as cotransporters

  4. secondary active transport

  5. proton pumps
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gases are non-polar and can cross the lipid bilayer with ease. They therefore, do not need specific mechanisms to cross the plasma membrane. The lipid bilayer is permeable to water molecules, oxygen and carbon dioxide. They diffuse freely in and out of the cell.

Multiple choice

The respiratory quotient is a dimensionless number used to calculate the basal metabolic rate. Which of the following substances has the highest value of RQ?

  1. Oxalic acid

  2. Tartaric acid

  3. Malic acid

  4. Tripalmitin

  5. Oleic acid
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Oleic acid is a fatty acid that occurs naturally in various animal and vegetable fats and oils. It is emitted by the decaying corpses of a number of insects, including bees and Pogonomyrmex ants. Its RQ value is 0.71.

Multiple choice

What is BOD?

  1. Amount of oxygen required for biological reduction

  2. Amount of oxygen required for biological phosphorylation

  3. Amount of oxygen required for biological oxidation

  4. None of these

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

It is the correct option as it is the amount of oxygen required for biological oxidation required by microbes in any unit volume of water. Full form of BOD is biological oxygen demand.

Multiple choice

Which among the following is oxygen as well as nitrogen carrier?

  1. Hemocyanins

  2. Hemoglobin

  3. Leghemoglobin

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

Leghemoglobin is both a nitrogen or oxygen carrier, because naturally occurring oxygen and nitrogen look the same to this protein and a hemoprotein found in the nitrogen-fixing root nodules of leguminous plants.

Multiple choice

The respiratory pigment found in humans is present in _____________________.

  1. plasma

  2. thrombocytes

  3. agranulocytes

  4. erythrocytes

  5. granulocytes
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Erythrocytes are the red blood cells. They contain the respiratory pigment, haemoglobin, which binds oxygen and help in carrying it to different cells of the body. Granulocytes are the white blood cells whose cytoplasm is granular. They are devoid of any pigment.