Breathing and Exchange of Gases

NEET Biology · 40 questions · Page 1 of 4 · Click an option or "Show Solution" to reveal answer

The exchange of gases in the alveoli of the lungs takes place by

A simple diffusion

B osmosis

C active transport

D passive transport

Correct Answer

Option A

Solution

(a) Gaseous exchange between blood and alveolar air occurs by simple diffusion.

Which one of the following organs in the human body is most affected due to shortage of oxygen?

A intestine

B skin

C kidney

D brain

Correct Answer

Option D

Solution

(d) Brain is the most vital organ and stops functioning in the absence of O2.

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

Correct Answer

Option A

Solution

(a) This is called chloride shift - bicarbonate ions diffuse out of RBCs while chloride ions enter to maintain ionic equilibrium.

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

Correct Answer

Option D

Solution

(d) Breathing becomes faster and deeper to oxygenate the blood at a fast rate.

Which two changes usually tend to occur in plain dwellers when they move to high altitudes?

A (ii) and (iii)

B (iii) and (iv)

C (i) and (iv)

D (i) and (ii)

Correct Answer

Option A

Solution

(a) At high altitude: increased breathing rate and increased red blood cell production.

Carbon dioxide is transported from tissues to respiratory surface by only

A plasma and erythrocytes

B plasma

C erythrocytes

D erythrocytes and leucocytes

Correct Answer

Option A

Solution

(a) CO2 is transported in plasma (dissolved and as bicarbonate) and in erythrocytes (as carbaminohaemoglobin).

Oxygen dissociation curve of haemoglobin is

A Sigmoid

B Hyperbolic

C Linear

D Hypobolic

Correct Answer

Option A

Solution

(a) The oxygen dissociation curve of haemoglobin is sigmoid (S-shaped).

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

Correct Answer

Option D

Solution

(d) Carbon dioxide is transported mostly as carbaminohaemoglobin and carbonic acid.

Although much CO2 is carried in blood, yet blood does not become acidic, because

A it is absorbed by the leucocytes

B blood buffers play an important role in CO2 transport.

C it combines with water to form H2CO3 which is neutralized by NaCO3

D it is continuously diffused through tissues and is not allowed to accumulate

Correct Answer

Option B

Solution

(b) Blood buffers (bicarbonate system) maintain the pH of blood.

Q10

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

Correct Answer

Option B

Solution

(b) Oxygen diffuses through the alveolar epithelium and the capillary endothelium into the capillary blood.

Ready for a full NEET mock test? Timed · full syllabus · detailed solutions after submission

Take a Mock Test →