MCQ Questions for Class 11 Biology: Ch 17 Breathing and Exchange of Gases
1. Oxygen dissociation curve of haemoglobin is:
(a) Sigmoid
(b) Hyperbolic
(c) Linear
(d) Hypobolic
► (a) Sigmoid
2. Air is breathed through:
(a) Trachea — lungs — larynx — pharynx — alveoli
(b) Nose — larynx — pharynx — bronchus — alveoli — bronchioles
(c) Nostrils — pharynx — larynx — trachea — bronchi — bronchioles — alveoli
(d) Nose — mouth — lungs
► (c) Nostrils — pharynx — larynx — trachea — bronchi — bronchioles — alveoli
3. The exchange of gases in the alveoli of the lungs takes place by:
(a) simple diffusion
(b) osmosis
(c) active transport
(d) passive transport
► (a) simple diffusion
4. Wall of alveoli is composed of
(a) Simple squamous epithelium
(b) Simple cuboidal epithelium
(c) Pseudostratified epithelium
(d) Simple columnar epithelium
► (a) Simple squamous epithelium
5. The lungs are enclosed in a covering called
(a) Perichondrium
(b) Pleural membrane
(c) Pericardium
(d) Peritoneum
► (b) Pleural membrane
6. People living at sea level have around 5 million RBC per cubic millimeter of their blood whereas those living at an altitude of 5400 metres have around 8 million. This is because at high altitude
(a) atmospheric O2 level is less and hence more RBCs are needed to absorb the required amount of O2 to survive
(a) atmospheric O2 level is less and hence more RBCs are needed to absorb the required amount of O2 to survive
(b) there is more UV radiation which enhances RBC production
(c) people eat more nutritive food, therefore more RBCs are formed
(d) people get pollution - free air to breathe and more oxygen is available
► (a) atmospheric O2 level is less and hence more RBCs are needed to absorb the required amount of O2 to survive
7. Increased asthmatic attacks in certain seasons are related to
(a) Inhalation of seasonal pollen
(b) Hot and humid environment
(c) Low temperature
(d) Eating fruits preserved in containers
► (a) Inhalation of seasonal pollen
8. What percentage of CO2 flows in blood in form of bicarbonates
(a) 7%
(b) 23%
(c) 50%
(d) 70%
► (d) 70%
9. Chloride shift for the transport of
(a) O2
(b) CO2
(c) CO
(d) Ozone
► (b) CO2
10. Cartilaginous rings in trachea are incomplete at which surface.
(a) Dorsal
(b) Ventral
(c) Lateral
(d) Ventrolateral
► (a) Dorsal
10. Cartilaginous rings in trachea are incomplete at which surface.
(a) Dorsal
(b) Ventral
(c) Lateral
(d) Ventrolateral
► (a) Dorsal
11. The two organisms which breathe only through their moist skin are
(a) Frog and earthworm
(b) Fish and frog
(c) Leech and earthworm
(d) Fish and earthworm
► (c) Leech and earthworm
12. Expiration involves
(a) Relaxation of diaphragm and intercostal muscles
(b) Contraction of diaphragm and intercostal muscles
(c) Contraction of diaphragm muscles
(d) Contraction of intercostal muscles
► (a) Relaxation of diaphragm and intercostal muscles
13. Thoracic cavity is enlarged by contraction of
(a) Internal Intercostal muscles
(b) Diaphragm
(c) Lungs
(d) All of above
► (b) Diaphragm
14. Book lungs are respiratory organs of
(a) Mammals
(b) Mollusca
(c) Earthworm
(d) Arachnida
► (d) Arachnida
15. The carbon dioxide is transported via blood to lungs as:
(a) dissolved in blood plasma
(b) in the form of carbonic acid only
(c) in combination with haemoglobin only
(d) carbaminohaemoglobin and as carbonic acid
► (d) carbaminohaemoglobin and as carbonic acid
16. Respiration in insects is direct due to exchange of gases
(a) Directly with the air outside through body surface
(b) By tracheal tubes directly with haemocoel which then exchange with tissues.
(c) Directly with coelomic fluid
(d) Directly with the air in tubes
► (b) By tracheal tubes directly with haemocoel which then exchange with tissues.
17. How oxygen enters in blood from alveoli of lungs
(a) Pressure of CO2
(b) Simple diffusion
(c) By Hb
(d) None of the Above
► (b) Simple diffusion
► (b) Simple diffusion
18. If TLC is 5500ml, IRV is 2950ml, ERV is 900ml and TV is 500ml then what will be value of RV?
(a) 2550ml
(b) 1100ml
(c) 1200ml
(d) 1150ml
► (d) 1150ml
19. How much oxygen, blood supplies to tissues in one circulation
(a) 75%
(b) 1.34%
(c) 25%
(d) 7%
► (c) 25%
20. During inspiration muscles of diaphragm
(a) Contracts
(b) Expands
(c) No effect
(d) Coiled like string
► (b) Expands
21. The alveolar epithelium in the lungs is:
(a) nonciliated columnar
(b) nonciliated squamous
(c) ciliated columnar
(d) ciliated squamous
► (b) nonciliated squamous
22. Habit of Cigarette smoking can lead to :
(a) loss of cilia lining the respiratory tract
(b) emphysema
(c) coughing
(d) All of the Above
► (d) All of the Above
23. Azygous lobe is part of
(a) Lung
(b) Kidney
(c) Larynx
(d) Palate
► (a) Lung
24. In alveoli of the lungs, the air at the site of gas exchange, is separated from the blood by
(a) alveolar epithelium only
(b) alveolar epithelium and capillary endothelium
(c) alveolar epithelium, capillary endothelium and tunica adventitia
(d) alveolar epithelium, capillary endothelium, a thin layer of tunica media and tunica adventitia
► (b) alveolar epithelium and capillary endothelium
25. Very high number of alveoli present in a lung is meant for
(a) More space for increasing volume of inspired air
(b) More area for diffusion
(c) Making the organ spongy
(d) Increasing nerve supply
► (b) More area for diffusion
26. The pneumotaxic centre is present in
(a) Medulla
(b) Cerebrum
(c) Cerebellum
(d) Pons varolii
► (d) Pons varolii
27. Intercostal muscles occur in:
(a) abdomen
(b) thigh
(c) ribs
(d) diaphragm
► (c) ribs
28. The regulatory centres for respiration are located in :
(a) Diencephalon and pons
(b) medulla oblongata & pons
(c) pons & cerebellum
(d) cerebellum and medulla oblongata\
► (b) medulla oblongata & pons
29. When CO2 concentration in blood increases, breathing becomes:
(a) shallower and slow
(b) there is no effect on breathing
(c) slow and deep
(d) faster and deeper
► (d) faster and deeper
► (d) faster and deeper
30. Which one of the following mammalian cells is not capable of metabolising glucose to carbon dioxide aerobically?
(a) Unstriated muscle cells
(b) White blood cells
(c) Liver cells
(d) Red blood cells
► (d) Red blood cells
31. The process of migration of chloride ions from plasma to RBC and of carbonate ions from RBC to plasma is:
(a) chloride shift
(b) ionic shift
(c) atomic shift
(d) Na+ pump
► (a) chloride shift
32. Opening to the trachea is covered by a small flap of tissues termed as the ______.
(a) Glottis
(b) Trachea
(c) Epiglottis
(d) Larynx
► (c) Epiglottis
33. Which one of the following mammalian cells is not capable of metabolising glucose to carbon-dioxide aerobically?
(a) unstraited muscle cells
(b) liver cells
(c) red blood cells
(d) white blood
► (c) red blood cells
34. A film of _____ lines lung alveoli that lowers _____ of the alveoli and makes breathing _____ :
(a) Lecithin, surface tension, easier.
(b) Pleuron, surface tension, easier.
(c) Cuticle, bacterial inflammation, difficult.
(d) Cuticle, inflating, difficult.
► (a) Lecithin, surface tension, easier.