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 statements is incorrect about oxygen?

  1. It is one of the major constituents of air.

  2. It is non-poisonous for anaerobic organisms.

  3. It is an essential component of nucleic acids and lipids.

  4. It is found as oxides of silicon in the earth's crust.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Oxygen is poisonous for anaerobic organisms as they work in the absence of oxygen.

Multiple choice

Oxygen is returned to the atmosphere through

  1. combustion

  2. respiration

  3. photosynthesis

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

Oxygen from the atmosphere is used up in three processes, namely combustion, respiration and in the formation of oxides of nitrogen. Oxygen is returned to the atmosphere in only one major process, i.e. photosynthesis. 

Multiple choice

Which of the following statements is/are false?

a. The process by which oxygen reacts with the digested food to form carbon dioxide, water vapour and heat energy is called respiration. b. Charcoal burns in air to produce carbon monoxide. c. Tall chimneys in factories carry harmful gases to the upper layers of air and prevent pollution of air to some extent.

  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
C Correct answer
Explanation

This is the correct option as this statement is false. Charcoal burns in air to produce carbon dioxide.

Multiple choice

Mountaineers carry oxygen cylinders on high altitudes because

  1. the volume of water vapours sharply decreases on high altitudes

  2. the volume of carbon dioxide sharply decreases on high altitudes

  3. the volume of nitrogen sharply increases on high altitudes

  4. the volume of oxygen sharply decreases on high altitudes

  5. the volume of carbon dioxide sharply increases on high altitudes
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This is the correct option. Mountaineers carry oxygen cylinders on high altitudes because the volume of oxygen sharply decreases on high altitudes.

Multiple choice

How does nicotine act in blood?

  1. Stimulates the nervous system

  2. Releases adrenaline

  3. Relaxes the muscles

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Nicotine is a stimulant that affects the nervous system, triggers the release of adrenaline, and can have varying effects on muscle tone, making all listed options correct.

Multiple choice

Pneumatophores are helpful in

  1. transpiration

  2. carbohydrate metabolism

  3. protein synthesis

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

Pneumatophores are specialized roots found in mangroves that grow upwards out of the waterlogged soil to facilitate gas exchange (respiration) in oxygen-deficient environments.

Multiple choice

Oxygen is transported in blood mainly by __________.

  1. blood platelets

  2. thrombocytes

  3. erythrocytes

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Erythrocytes, or red blood cells, contain hemoglobin, which is the protein responsible for binding and transporting oxygen in the blood.

Multiple choice

One gram haemoglobin can combine with

  1. 1.3 ml oxygen

  2. 3.5 ml oxygen

  3. 3.1 ml oxygen

  4. 31 ml oxygen
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

One gram of hemoglobin can bind approximately 1.34 ml of oxygen, often rounded to 1.3 ml in textbook contexts.

Multiple choice

In the tissues, high concentration of carbon dioxide

  1. increases the affinity of haemoglobin to both oxygen and hydrogen

  2. increases the affinity of haemoglobin to oxygen but decreases its affinity to hydrogen

  3. decreases the affinity of haemoglobin to oxygen but increases its affinity to hydrogen

  4. decreases the affinity of haemoglobin to both oxygen and hydrogen
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The Bohr effect states that high CO2 concentrations increase hydrogen ion concentration (lower pH), which decreases hemoglobin's affinity for oxygen, facilitating oxygen release in tissues.

Multiple choice

Which of the following statements is correct?

  1. All animals require a medium for respiration.

  2. In all animals, oxygen is transported by blood.

  3. In all animals, oxygen is taken in from water or air through gills or lungs.

  4. All animals need oxygen for respiration.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

All living cells require a medium for gas exchange, which is typically a moist surface. Option B is false because some animals use diffusion directly; C is false because many animals use skin or tracheae; D is false because some organisms are anaerobic.

Multiple choice

Oxygen dissociation curve shifts to right in case of presence of

  1. high CO2 concentration

  2. low CO2 concentration

  3. chemical like DPG

  4. both 1 and 3
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The oxygen dissociation curve shifts to the right (Bohr effect) when hemoglobin's affinity for oxygen decreases. This occurs in conditions of high CO2 concentration, low pH, high temperature, and increased levels of 2,3-DPG.

Multiple choice

A condition in which body's internal environment remains relatively constant within limits is called

  1. homeostasis

  2. hemostasis

  3. hematoma

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

A condition in whcih body's internal environment remains relatively constant within limits is called homeostasis homeostatic mechanisms protects an animal's internal environment form harmful fluctuations. It enables animals to survive large flucuations in theri external environment by tempering changes in body fluids. 

Multiple choice

Which among the following gases hampers the transport of oxygen in our body by replacing oxygen in oxyhaemoglobin?

  1. Carbon dioxide

  2. Carbon monoxide

  3. Carbon disulphide

  4. Carbon carbide
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Carbon monoxide hampers the transport of oxygen in our body. In lungs, oxygen combines with haemoglobin present in blood and is transported to all parts of the body. However, carbon monoxide if inhaled, displaces oxygen and forms carboxyhaemoglobin.