Q1. What is the average percentage of plasma in human blood?
a) 45%
b) 55%
c) 60%
d) 70%
Show Answer
Correct Answer: b) 55%
Explanation: Plasma is the liquid component of blood and makes up about 55% of its total volume. It is primarily composed of water (90%), with the remainder consisting of proteins, glucose, clotting factors, electrolytes, hormones, carbon dioxide, and oxygen.
Q2. Which of the following is a major component of red blood cells?
a) Hemoglobin
b) Insulin
c) Plasma
d) Platelets
Show Answer
Correct Answer: a) Hemoglobin
Explanation: Hemoglobin is the key component of red blood cells. It is an iron-containing protein that binds oxygen in the lungs and delivers it to tissues throughout the body. Hemoglobin gives red blood cells their characteristic color.
Q3. What is the primary function of white blood cells?
a) Transporting oxygen
b) Blood clotting
c) Fighting infections
d) Carrying nutrients
Show Answer
Correct Answer: c) Fighting infections
Explanation: White blood cells, or leukocytes, are crucial for the immune system. They protect the body against both infectious disease and foreign invaders. Several types of white blood cells work together to identify and destroy pathogens.
Q4. Platelets in the blood are essential for:
a) Oxygen transport
b) Blood clotting
c) Nutrient transport
d) Immune response
Show Answer
Correct Answer: b) Blood clotting
Explanation: Platelets, or thrombocytes, are small cell fragments in the blood that are crucial for blood clotting. They gather at the site of a blood vessel injury, stick to the lining of the injured blood vessel, and form a platform on which blood coagulation can occur.
Q5. What percentage of blood is composed of cells?
a) About 25%
b) About 45%
c) About 60%
d) About 75%
Show Answer
Correct Answer: b) About 45%
Explanation: Blood cells, including red blood cells, white blood cells, and platelets, make up about 45% of the blood’s volume. The remaining 55% is plasma. The high percentage of red blood cells is the main contributor to this cellular fraction.
Q6. Which protein in blood plasma plays a key role in maintaining osmotic pressure?
a) Fibrinogen
b) Albumin
c) Globulin
d) Hemoglobin
Show Answer
Correct Answer: b) Albumin
Explanation: Albumin is a protein in blood plasma that plays a critical role in maintaining the osmotic pressure necessary for proper distribution of body fluids between blood vessels and body tissues. It also transports hormones, vitamins, drugs, and ions like calcium.
Q7. Which type of white blood cell is primarily responsible for antibody production?
a) Neutrophils
b) Eosinophils
c) Lymphocytes
d) Monocytes
Show Answer
Correct Answer: c) Lymphocytes
Explanation: Lymphocytes are a type of white blood cell that play a significant role in the body’s immune response. They are primarily responsible for the production of antibodies, which are proteins that specifically target and neutralize foreign substances such as bacteria and viruses.
Q8. The lifespan of a typical red blood cell is approximately:
a) 30 days
b) 60 days
c) 120 days
d) 240 days
Show Answer
Correct Answer: c) 120 days
Explanation: The average lifespan of a human red blood cell is about 120 days. After this period, aged red blood cells are typically removed from circulation by the spleen and liver, where they are broken down and their components recycled.
Q9. What is the main function of fibrinogen in blood plasma?
a) Transporting nutrients
b) Regulating pH
c) Blood clotting
d) Fighting infections
Show Answer
Correct Answer: c) Blood clotting
Explanation: Fibrinogen is a soluble protein present in blood plasma that plays a critical role in blood clot formation. During the clotting process, fibrinogen is converted by thrombin into fibrin, which forms a mesh that traps blood cells and forms a stable clot.
Q10. An increase in the number of which cell is typically seen in allergic reactions?
a) Neutrophils
b) Eosinophils
c) Basophils
d) Lymphocytes
Show Answer
Correct Answer: b) Eosinophils
Explanation: Eosinophils are a type of white blood cell that are typically increased in number during allergic reactions. They play a key role in the body’s response to allergens and are also involved in the response to parasitic infections.