Grade 11 : Biology - Breathing and Gas Exchange in Animals (Set 3)

Question 1

Respiratory Gas	Atmospheric Air	Alveoli	Deoxygenated Blood	Oxygenated Blood	Tissues
$O_2$	159 mm Hg	104 mm Hg	40 mm Hg	$X$ mm Hg	40 mm Hg
$CO_2$	0.3 mm Hg	40 mm Hg	45 mm Hg	40 mm Hg	$Y$ mm Hg

Based on standard physiological partial pressures of gases, identify the missing values $X$ and $Y$ in the table.

Accepted Answer

A) X = 95 mm Hg, Y = 45 mm Hg

Answer

B) X = 104 mm Hg, Y = 40 mm Hg

Answer

C) X = 40 mm Hg, Y = 95 mm Hg

Answer

D) X = 45 mm Hg, Y = 104 mm Hg

Question 2

A clinical spirogram recorded for an adult male shows a Tidal Volume (TV) of 500 mL, an Inspiratory Reserve Volume (IRV) of 2500 mL, an Expiratory Reserve Volume (ERV) of 1100 mL, and a Residual Volume (RV) of 1200 mL.

Calculate the Vital Capacity (VC) of this individual.

Accepted Answer

B) 4100 mL

Answer

A) 3000 mL

Answer

C) 5300 mL

Answer

D) 3600 mL

Question 3

Graph representation: Oxygen-Haemoglobin Dissociation Curve showing percentage saturation of haemoglobin versus partial pressure of oxygen ($pO_2$).

Which of the following physiological conditions shifts the Oxygen-Haemoglobin Dissociation Curve to the right?

Accepted Answer

C) Low $pO_2$, high $pCO_2$, high $H^+$ concentration, and higher temperature

Answer

A) High $pO_2$, low $pCO_2$, low $H^+$ concentration, and low temperature

Answer

B) Low $pCO_2$, high pH, and lower body temperature

Answer

D) High $pO_2$, high pH, and low metabolic rate

Question 4

Match the organism with its primary mode/organ of respiration:
1. Earthworm — (i) Tracheal tubes
2. Cockroach — (ii) Moist cuticle
3. Aquatic Arthropods — (iii) Gills
4. Flatworms — (iv) Simple body surface diffusion

Which matching combination is correct?

Accepted Answer

A) 1-(ii), 2-(i), 3-(iii), 4-(iv)

Answer

B) 1-(i), 2-(ii), 3-(iii), 4-(iv)

Answer

C) 1-(ii), 2-(iii), 3-(i), 4-(iv)

Answer

D) 1-(iv), 2-(i), 3-(iii), 4-(ii)

Question 5

During quiet inspiration, specific muscle contractions expand the thoracic cavity volume, lowering intra-pulmonary pressure below atmospheric pressure.

Which pair of muscles is primarily responsible for initiating normal quiet inspiration?

Accepted Answer

D) Diaphragm and external intercostal muscles

Answer

A) Internal intercostal muscles and abdominal muscles

Answer

B) External intercostal muscles and abdominal muscles

Answer

C) Diaphragm and internal intercostal muscles

Question 6

$CO_2 + H_2O \xrightleftharpoons[ ext{Enzyme}]{\quad} H_2CO_3 \xrightleftharpoons[ ext{Enzyme}]{\quad} HCO_3^- + H^+$

Which enzyme, present in extremely high concentrations inside Red Blood Cells (RBCs), catalyzes both forward and reverse directions of this reaction?

Accepted Answer

B) Carbonic anhydrase

Answer

A) Haemoglobinase

Answer

C) Carboxypeptidase

Answer

D) Lactate dehydrogenase

Question 7

An athlete's Expiratory Reserve Volume (ERV) is measured at 1100 mL and Residual Volume (RV) is 1200 mL.

What is the athlete's Functional Residual Capacity (FRC)?

Accepted Answer

C) 2300 mL

Answer

A) 1700 mL

Answer

B) 3600 mL

Answer

D) 2800 mL

Question 8

Neural regulation fine-tunes the human respiratory rhythm. A specialized center located in the pons region of the brain can moderate the functions of the respiratory rhythm center.

What is the name of this neural center located in the pons?

Accepted Answer

A) Pneumotaxic center

Answer

B) Chemosensitive area

Answer

C) Apneustic center

Answer

D) Medullary rhythm center

Question 9

A long-term smoker presents with chronic shortness of breath. Medical imaging shows damage to the alveolar walls and significant loss of alveolar respiratory surface area.

Which respiratory disorder is the patient suffering from?

Accepted Answer

D) Emphysema

Answer

A) Asthma

Answer

B) Silicosis

Answer

C) Pneumonia

Question 10

Workers in stone-breaking and grinding industries are exposed to heavy dust containing silica and asbestos, leading to chronic lung inflammation.

What major pathological change occurs in the lungs during such occupational respiratory disorders?

Accepted Answer

B) Proliferation of fibrous tissue (fibrosis) causing severe lung damage

Answer

A) Breakdown of alveolar septa leading to air trapping

Answer

C) Spasm of bronchial smooth muscles causing wheezing

Answer

D) Accumulation of fluid in alveoli due to bacterial infection

Question 11

A climber ascends to an altitude above 3500 meters where atmospheric pressure and $pO_2$ are low, experiencing altitude sickness. Over two weeks, their body acclimates.

Which physiological compensatory mechanism takes place during high altitude acclimatization?

Accepted Answer

C) Increased RBC production, increased breathing rate, and decreased binding affinity of haemoglobin

Answer

A) Decreased RBC production and decreased breathing rate

Answer

B) Increased binding affinity of haemoglobin for oxygen

Answer

D) Decreased heart rate and decreased total blood volume

Question 12

A healthy human has a Tidal Volume of 500 mL and a resting breathing rate of 14 breaths per minute.

What is the total minute volume of ventilation (volume of air inspired/expired per minute)?

Accepted Answer

A) 7000 mL/min

Answer

B) 5000 mL/min

Answer

C) 12000 mL/min

Answer

D) 3500 mL/min

Question 13

Carbon dioxide is transported through the bloodstream from body tissues to the lungs in three distinct physical/chemical states.

What percentage of $CO_2$ is transported bound to haemoglobin as carbamino-haemoglobin?

Accepted Answer

D) 20 - 25%

Answer

A) 70%

Answer

B) 7%

Answer

C) 97%

Question 14

Anatomical order: Nostrils → Nasal passage → Pharynx → Larynx → Trachea → Primary Bronchi → Bronchioles → Alveoli.

Which section of the human respiratory tract is shared as a common passage for both food and air?

Accepted Answer

B) Pharynx

Answer

A) Larynx

Answer

C) Trachea

Answer

D) Nasal chamber

Question 15

During forceful expiration, internal intercostal muscles and abdominal muscles contract actively to reduce thoracic volume.

What happens to the shape of the diaphragm during expiration when it relaxes?

Accepted Answer

A) It returns to its normal dome shape

Answer

B) It becomes completely flattened

Answer

C) It moves laterally toward the rib cage

Answer

D) It expands outward into the abdominal cavity

Question 16

Consider the following statements regarding the diffusion membrane in human lungs:
Statement I: The diffusion membrane is made up of three major layers: thin squamous epithelium of alveoli, endothelium of alveolar capillaries, and the basement substance in between.
Statement II: The total thickness of the diffusion membrane is greater than 5 millimeters to prevent capillary rupture.

Which of the statements given above is/are correct?

Accepted Answer

C) Statement I is correct but Statement II is incorrect

Answer

A) Both Statement I and Statement II are correct

Answer

B) Both Statement I and Statement II are incorrect

Answer

D) Statement I is incorrect but Statement II is correct

Question 17

The chemosensitive area situated adjacent to the respiratory rhythm center in the medulla is highly sensitive to changes in blood composition.

Which chemicals stimulate this chemosensitive area to send signals for respiratory rhythm adjustments?

Accepted Answer

B) High $CO_2$ and high $H^+$ ion concentration

Answer

A) High $O_2$ concentration and low $CO_2$

Answer

C) Low $CO_2$ and low $H^+$ ion concentration

Answer

D) Low $O_2$ concentration only

Question 18

A clinical pulmonary test reports the following parameters: Total Lung Capacity (TLC) = 5800 mL, Residual Volume (RV) = 1200 mL, and Inspiratory Capacity (IC) = 3500 mL.

Calculate the Expiratory Reserve Volume (ERV).

Accepted Answer

D) 1100 mL

Answer

A) 2300 mL

Answer

B) 1500 mL

Answer

C) 800 mL

Question 19

In an enclosed room with a faulty gas heater, carbon monoxide (CO) accumulates. Inhaling CO causes tissue hypoxia even when arterial $pO_2$ remains normal.

Why is Carbon Monoxide extremely toxic to human respiration?

Accepted Answer

A) CO binds to haemoglobin with about 200 times higher affinity than $O_2$, forming stable carboxyhaemoglobin

Answer

B) CO destroys the surfactant lining of alveolar membranes instantly

Answer

C) CO inhibits carbonic anhydrase enzyme in blood plasma

Answer

D) CO paralyzes the diaphragm muscles directly

Question 20

Every 100 mL of oxygenated blood delivers a specific amount of $O_2$ to tissues under normal physiological conditions.

How much oxygen is delivered to tissues by 100 mL of oxygenated blood under normal resting conditions?

Accepted Answer

C) 5 mL

Answer

A) 15 mL

Answer

B) 20 mL

Answer

D) 4 mL

Grade 11 : Biology - Breathing and Gas Exchange in Animals (Set 3)