Which of the following is a protein present in blood plasma?
A.
Monocytes
B.
Platelets
C.
Fibrinogen
D.
Lymphocytes
The Correct Answer and Explanation is :
The correct answer is C. Fibrinogen.
Explanation:
Blood plasma is the liquid component of blood that carries cells, hormones, nutrients, and waste products throughout the body. It makes up about 55% of the total blood volume. Plasma is composed mainly of water (approximately 90%) and contains a variety of proteins, electrolytes, and other substances.
Fibrinogen is a key protein present in blood plasma. It plays a critical role in the clotting process, which is essential for stopping bleeding and facilitating wound healing. When a blood vessel is injured, fibrinogen is converted into fibrin by the enzyme thrombin. Fibrin strands form a mesh-like structure that traps blood cells and platelets, creating a stable blood clot. This process is crucial for hemostasis, the mechanism that prevents excessive bleeding after vascular injury.
To understand the roles of the other options:
- A. Monocytes are a type of white blood cell found in the blood. They are part of the immune system and help in fighting off infections and removing dead cells. Monocytes are not proteins but rather cellular components of blood.
- B. Platelets (or thrombocytes) are cell fragments involved in blood clotting. They aggregate at the site of a blood vessel injury and help to form the initial plug that, together with fibrin, stops bleeding. While they are crucial for clotting, they are not proteins.
- D. Lymphocytes are another type of white blood cell involved in the immune response, specifically in recognizing and responding to pathogens and abnormal cells. Like monocytes, they are not proteins but cellular components.
In summary, fibrinogen is a plasma protein that is vital for coagulation and is essential in the clotting cascade. The other options, while important for blood function and immune responses, are not proteins present in plasma.