Question of Exercise 3

Circulatory System of Class 11

The main function of lymphocytes is


Option 1 To destroy poisonous substances present in the body

Option 2 To clot the blood at the site of a wound

Option 3 To carry oxygen to different parts of the body

Option 4 To destroy bacteria

Frequently Asked Questions

The liquid portion of the blood is called as

A: Plasma

B: Leucocyte

C: Serum

D: None of the above


Explanation :- 

Plasma comprises about 55% of the blood part.

Plasma is made up of 90% water, and rest salts and proteins.

It functions as a liquid portion of the blood.

The other name of leukocytes is white blood cells.

They lack respiratory pigment, i.e hemoglobin.

They provide protection against foreign particles.

Serum, the fluid portion of the blood without clotting factors and blood cells.

Final answer :- 

The correct answer is plasma, i.e option (A).

The inner membrane of mitochondria is folded because

A: It has no space inside.

B: It helps in transportation of material.

C: It increases the surface area.

D: It stores more food.



Mitochondria is a double membrane bound structure.

It has two membranes,i.e outer and inner membrane.

Outer membrane of mitochondria is continuous while the inner membrane has folds called cristae.

Cristae provides a large surface area for the chemical reactions to occur.

These folds increase the capacity of mitochondria to produce more ATP molecules.

Inside the inner membrane, a matrix is also present.

They do not transport materials. They are sites of ATP synthesis.

They do not store food. They just provide an area for ATP synthesis.

Final answer:

The correct answer is it increases the surface area, i.e option (C ).

Name the scientist who introduced the term protoplasm



  • Protoplasm is the living part of the cell covered by a plasma membrane. 
  • The term protoplasm was first coined by J.E. Purkinje in 1839.

Final Answer:

J.E. Purkinje introduced the term protoplasm.


Blood platelets help in the blood coagulation mechanism by liberation of

A: Thromboplastin

B: Thrombin

C: Prothrombin

D: None of the above



Blood coagulation is initiated by the thromboplastin. 

It is also called a tissue factor.

They help in the conversion of prothrombin to thrombin. 

With the help of calcium ions and other clotting factors, they convert prothrombin to thrombin.

They are released by blood platelets at the point of injury.

Final answer:

The correct answer is thromboplastin, i.e option (A).

Lysosomes are formed by


B: Mitochondria

C: Ribosomes

D: None of these



Lysosomes are single membrane bound, spherical organelles. 

They are known as suicidal bag of the cell because they are digestive in nature. 

They contain hydrolytic enzymes.

They are formed by golgi bodies.

ER, mitochondria and ribosomes do not produce lysosomes.

Final answer:

The correct option is none of these, i.e option (D).

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