Question

Blood cells that show phagocytosis are
A. platelets
B. eosinophils
C. basophils
D. monocytes

Answer 1

Phagocytosis is mainly the process by which the particles or the other cells are engulfed. We know that there are only two types of white blood cells that show phagocytosis. In higher organisms, it is chiefly associated with the defence mechanism.

Complete answer:
We know that phagocytosis is the process in which certain living cells called phagocytes engulfs the other cells or the particles. They may be free-living as in amoeba. In some animals, this is the means of engulfing food whereas in higher animals phagocytosis is chiefly a defensive reaction against many infections in the body by any foreign particle.

A) Platelets are also called thrombocytes that are tiny fragments of cells that are essential for normal blood clotting. Their role is mainly the healing of a wound by forming a dense layer of thread-like structures on them.
B) Eosinophils are white blood cells that help to fight against diseases. They resist infections and also are associated with all the allergic reactions taking place in the body.
C) Basophils are also a type of white blood cells. They are produced in the bone marrow throughout the body. They play a major role in the ability to detect and destroy cancer cells. They secrete histamine, serotonin and heparin that are involved in inflammatory reactions.
C) Monocytes are a type of leukocytes or WBC. They are the largest type of leukocytes. We know that there are two types of WBC i.e agranulated and granulated. Lymphocytes and monocytes are categorized under agranulocytes and neutrophils, eosinophils and basophils are under granulocytes.
We know that only neutrophils and monocytes (6-8 per cent) are phagocytic cells that destroy foreign organisms entering the body.

Monocytes are found in the bloodstream and they circulate around the body. When tissue is infected these cells enter the tissue leaving the bloodstream where they differentiate and increase in number at the point of inflammation. They are the largest types of phagocytes bearing a kidney bean-shaped nucleus when observed under the microscope.

Therefore the correct answer is option ‘D’.

Note: Leukocytes are called white blood cells as they are colourless due to the lack of haemoglobin. They are nucleated and are relatively lesser in number which averages 6000- 8000 mm of blood. They are generally short-lived. Monocytes are a type of leukocytes. They perform phagocytosis using intermediate proteins like antibodies which usually coat the pathogen as well as they also bind to the microbes directly.