CBSE Class 11 (Science) Breathing and Exchange of Gases — practice questions
90 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice CBSE Class 11 (Science) Breathing and Exchange of Gases in the app →Gas exchange between alveolar air and blood is driven byVital capacity of the lungs is the sum ofDuring quiet inspiration, the diaphragmThe actual exchange of O₂ and CO₂ between blood and air happens at theWhich structure belongs to the conducting (not respiratory) zone?Insects breathe throughResidual volume (RV) isSurfactant in the alveoliOne haemoglobin molecule can carry a maximum of how many oxygen molecules?Most CO₂ is transported in the blood asThe basic respiratory rhythm is generated in theEmphysema is most commonly caused byCarbon monoxide poisoning is dangerous because COA sponge has no lungs or gills. It exchanges gases by:An earthworm breathes through its:A frog can also breathe through its moist skin. This is called:The pharynx is a passage shared by:The larynx is called the sound box because it helps in:While you swallow, a flap covers the glottis so food does not enter the larynx. The flap is the:The trachea and bronchi stay open because they are supported by incomplete rings of:The tiny thin-walled bags at the end of each terminal bronchiole are the:Air enters the lungs when the pressure inside the lungs is:External intercostal muscles contract and:A healthy adult at rest breathes about ___ times a minute.The device that measures the volumes of air moved in breathing is a:The air you breathe in or out in one normal breath, about 500 mL, is the:After a normal breath you force in extra air. That extra amount is the:Gases cross from alveoli to blood mainly by:About 97 percent of oxygen in blood is carried by:Haemoglobin is red because it contains:Oxygen binds haemoglobin in the lungs and leaves it at the:Every 100 mL of oxygenated blood delivers about ___ of oxygen to the tissues.The enzyme in red cells that speeds up carbon dioxide and water turning into bicarbonate is:Wheezing from inflamed bronchi and bronchioles is:A stone-crusher works for years in dust and develops lung fibrosis. Such workers should wear:Which structure do earthworms use for gas exchange?Which network of tubes carries air within an insect's body?What do most aquatic arthropods and molluscs use for gas exchange?How do sponges and flatworms exchange gases?Which flap covers the glottis during swallowing to keep food out of the larynx?At the level of which vertebra does the trachea divide into two primary bronchi?What supports the trachea and the initial bronchioles?Terminal bronchioles give rise to which bag-like exchange structures?What covers the two lungs in humans?Which part of the human respiratory system runs from the external nostrils to the terminal bronchioles?Which of these is a job of the conducting part of the respiratory system?Where does actual diffusion of O2 and CO2 between blood and air occur?Which structure forms the ventral boundary of the thoracic chamber?Which step of respiration is called pulmonary ventilation?Inspiration occurs when the pressure inside the lungs is what relative to the atmosphere?What is the intra-pulmonary pressure like during expiration?Which muscles, along with the diaphragm, help generate pressure gradients for breathing?What does contraction of the diaphragm do to the thoracic chamber?What does contraction of the external intercostal muscles do?How many times per minute does a healthy human breathe on average?Which instrument estimates the volume of air in breathing movements?What is the approximate tidal volume of a healthy adult?A healthy man can inspire or expire about how much air per minute?Which volume is the extra air a person can take in by forcible inspiration?Roughly how much air does forcible inspiration add above tidal volume?How much air can be forcibly expired after a normal expiration?Which volume of air stays in the lungs even after a forcible expiration?What is inspiratory capacity made up of?Expiratory capacity is the sum of which two volumes?Which two volumes add up to functional residual capacity?Vital capacity includes which volumes?By what process are O2 and CO2 exchanged across alveoli and tissues?What is the pressure contributed by one gas in a gas mixture called?How does the solubility of CO2 compare with that of O2?How many major layers form the diffusion membrane in the alveolus?Which cell layer lines the alveoli in the diffusion membrane?What share of oxygen travels dissolved in plasma?In what form is about 70 per cent of CO2 transported in blood?About what percentage of CO2 is carried by haemoglobin as carbamino-haemoglobin?About what percentage of CO2 is carried dissolved in plasma?Which red iron-containing pigment of RBCs binds oxygen?What is the maximum number of O2 molecules one haemoglobin molecule can carry?What compound forms when oxygen reversibly binds haemoglobin?What shape is the oxygen dissociation curve of haemoglobin?Which condition set in the alveoli favours formation of oxyhaemoglobin?How much oxygen can 100 mL of oxygenated blood normally deliver to tissues?Which enzyme, abundant in RBCs, drives the reaction of CO2 and H2O to bicarbonate?Which region of the brain holds the respiratory rhythm centre?What does a signal from the pneumotaxic centre do to inspiration?Which two substances most strongly activate the chemosensitive area near the rhythm centre?Which blood vessels carry receptors that sense CO2 and H+ changes?What role does oxygen play in regulating respiratory rhythm?In which disorder are alveolar walls damaged, reducing respiratory surface?What is a major cause of emphysema?Long exposure to dust in grinding industries causes which lung change?