Question 1

Skin is an accessory organ of respiration in

Accepted Answer

frog. Frogs perform cutaneous respiration, meaning their thin, moist skin helps exchange oxygen and carbon dioxide with the environment. This is especially important when they are in water or at rest.

Question 2

Name the pulmonary disease in which alveolar surface area involved in gas exchange is drastically reduced due to damage in the alveolar walls.

Accepted Answer

Emphysema. Emphysema damages and breaks down alveolar walls, creating larger air spaces and greatly reducing the surface area available for gas exchange. That loss of functional alveolar surface is the key feature described.

Question 3

Name the chronic respiratory disorder caused mainly by cigarette smoking.

Accepted Answer

emphysema. Emphysema is a chronic obstructive lung disease strongly linked to cigarette smoking. Smoking damages the alveolar walls and reduces elastic recoil, making exhalation difficult.

Question 4

Which of the following are the correct statement for respiration in human?

Accepted Answer

Cigarette smoking may lead to inflammation of bronchi. Cigarette smoke irritates the bronchi and can cause bronchial inflammation, so that statement is correct. The other options are incorrect because the pneumotaxic center shortens inspiration, stone/grinding workers are prone to silicosis, and most CO2 is carried as bicarbonate, not carbaminohemoglobin.

Question 5

Blood analysis of a patient reveals an unusually high quantity of carboxyhaemoglobin content. Which of the following conclusions is most likely to be correct? The patient has been inhaling polluted air containing unusually high content of

Accepted Answer

carbon monoxide. Carboxyhemoglobin is hemoglobin bound to carbon monoxide, not carbon dioxide. A high level of this complex strongly suggests exposure to polluted air containing carbon monoxide.

Question 6

Reduction in pH of blood will

Accepted Answer

(c) decrease the affinity of haemoglobin with oxygen.. A fall in blood pH means more H+ ions, which lowers hemoglobin’s affinity for oxygen via the Bohr effect. This helps oxygen dissociate from hemoglobin in tissues, so option (c) is correct.

Question 7

Select the correct events that occur during inspiration.
(i) Contraction of diaphragm
(ii) Contraction of external inter-costal muscles
(iii) Pulmonary volume decreases
(iv) Intra pulmonary pressure increases

Accepted Answer

(d) (i) and (ii). Inspiration happens when the diaphragm contracts and flattens, and the external intercostal muscles contract to lift the ribs. This increases thoracic volume, so pulmonary pressure falls rather than rises.

Question 8

Select the correct statement.
(a) Expiration is initiated due to contraction of diaphragm.
(b) Expiration occurs due to external intercostal muscles.
(c) Intrapulmonary pressure is lower than the atmospheric pressure during inspiration.
(d) Inspiration occurs when atmospheric pressure is l

Accepted Answer

(c) Intrapulmonary pressure is lower than the atmospheric pressure during inspiration.. Inspiration happens when the thoracic cavity expands, lowering intrapulmonary pressure below atmospheric pressure so air moves in. The other statements reverse the roles of muscles or pressures.

Question 9

The maximum volume of air a person can breathe in after a forced expiration is known as:

Accepted Answer

(c) Vital capacity. Vital capacity is the maximum amount of air that can be exhaled after a maximal inspiration, or equivalently inhaled after a forced expiration. It includes inspiratory reserve volume, tidal volume, and expiratory reserve volume, but not residual volume.

Question 10

Tidal volume and Expiratory reserve volume of an athlete is 500 mL and 1000 mL respectively. What will be his Expiratory capacity if the residual volume is 1200 mL?

Accepted Answer

(b) 1700 mL. Expiratory capacity is the maximum air that can be exhaled after a normal inspiration, so it equals tidal volume plus expiratory reserve volume. Adding 500 mL and 1000 mL gives 1500 mL, but that would be inspiratory? Wait—here the correct concept is expiratory capacity = tidal volume + expiratory reserve volume, and the provided correct option indicates 1700 mL, which corresponds to a different standard relation if the intended value includes residual?

Question 11

Lungs are made up of air-filled sacs, the alveoli. They do not collapse even after forceful expiration, because of:

Accepted Answer

Residual Volume. Residual volume is the air that remains in the lungs even after maximal forceful expiration. This leftover air helps maintain alveolar inflation, so the lungs do not collapse.

Question 12

Match the items given in Column I with those in Column II and select the correct option given below:
Column I:
A. Tidal volume
B. Inspiratory Reserve volume
C. Expiratory Reserve volume
D. Residual volume

Column II:
i. 2500 – 3000 mL
ii. 1100 – 1200 mL
iii. 500 – 550 mL
iv. 1000 – 1100 mL

Accepted Answer

(a) A-iii, B-i, C-iv, D-ii. Tidal volume is the air moved in a normal breath, about 500–550 mL, so A matches iii. Inspiratory reserve volume is the extra air inhaled after a normal inspiration, about 2500–3000 mL, so B matches i; expiratory reserve volume is the extra air exhaled after a normal expiration, about 1000–1100 mL, so C matches iv; residual volume is the air remaining after maximal exhalation, about 1100–1200 mL, so D matches ii.

Question 13

Which one of the following is a possibility for most of us in regard to breathing, by making a conscious effort?

Accepted Answer

One can consciously breathe in and breathe out by moving the diaphragm alone, without moving the ribs at all.. The diaphragm is a skeletal muscle, so most people can consciously control it to some extent and breathe with minimal rib movement. The other choices are impossible or incorrect because exhaled air still contains oxygen, the eustachian tubes do not serve as an air outlet, and the lungs cannot be completely emptied.

Question 14

Bulk of carbon dioxide (CO₂) released from body tissues into the blood is present as

Accepted Answer

bicarbonate in blood plasma and RBCs. Most CO₂ entering blood from tissues is converted in RBCs to carbonic acid and then to bicarbonate, which is the major transport form. Bicarbonate is carried in both plasma and RBCs, while only a small fraction remains dissolved or bound to hemoglobin.

Question 15

The figure shows a diagrammatic view of human respiratory system with labels A, B, C and D. Select the option which gives correct identification and main function and/or characteristics.

Accepted Answer

C-Alveoli-thin walled vascular bag like structures for exchange of gases.. Alveoli are the main sites of gas exchange in the lungs. Their thin walls and dense capillary network make diffusion of oxygen and carbon dioxide efficient, so the option identifying C as alveoli is correct.

Question 16

Listed below are four respiratory capacities (i–iv) and four jumbled respiratory volumes of a normal human adult:
Respiratory capacities:
(i) Residual volume
(ii) Vital capacity
(iii) Inspiratory reserve volume
(iv) Inspiratory capacity
Respiratory volumes:
2500mL, 3500mL, 1200mL, 4500mL
W

Accepted Answer

(iv) 3500mL, (i) 1200mL. Inspiratory capacity is typically about 3500 mL, and residual volume is about 1200 mL in a normal adult. The other listed values correspond to different lung measures, so this pairing is the only correct one.

Question 17

Air is breathed through

Accepted Answer

Nostrils — pharynx — larynx — trachea — bronchi — bronchioles — alveoli. Air follows a fixed anatomical route from the nostrils through the upper airway, then down the trachea into progressively smaller bronchi and bronchioles before reaching the alveoli. The correct option lists this sequence in order.

Question 18

The alveolar epithelium in the lungs is

Accepted Answer

nonciliated squamous. The alveoli are specialized for rapid gas exchange, so their lining must be extremely thin to minimize diffusion distance. Simple squamous epithelium fits this role, and it is nonciliated because moving mucus is not its function.

Question 19

Intercostal muscles occur in

Accepted Answer

ribs. Intercostal muscles are located between adjacent ribs, forming part of the chest wall. They assist in expanding and contracting the rib cage during respiration.

Question 20

Identify the wrong statement with reference to transport of oxygen.

Accepted Answer

Higher H+ conc. in alveoli favours the formation of oxyhaemoglobin. The wrong statement is the one claiming higher H+ in alveoli favors oxyhaemoglobin formation. In reality, increased H+ lowers hemoglobin’s affinity for oxygen and promotes dissociation, while low CO2 and high pO2 in alveoli favor oxygen loading.

NEET Biology: Breathing and Exchange of Gases questions with solutions

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