Q1. What percentage of the human body’s weight is made up of blood?
a) 2-4%
b) 7-8%
c) 10-12%
d) 15-17%
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Correct Answer: b) 7-8%
Explanation: Blood typically accounts for about 7-8% of the human body’s weight. For an average adult, this translates to approximately 4.5 to 5.5 liters of blood. This blood plays a critical role in transportation, regulation, and protection within the body.
Q2. Red blood cells are produced in the:
a) Liver
b) Spleen
c) Bone marrow
d) Kidneys
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Correct Answer: c) Bone marrow
Explanation: Red blood cells are produced in the bone marrow, the soft, fatty tissue inside bone cavities. The bone marrow is a primary site of hematopoiesis, the process by which all blood cells are generated, including red blood cells, white blood cells, and platelets.
Q3. Which of the following blood groups is considered the universal recipient?
a) A+
b) B+
c) AB+
d) O+
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Correct Answer: c) AB+
Explanation: AB+ blood type is considered the universal recipient in the context of red blood cell transfusions because individuals with this blood type have both A and B antigens on their red cells but do not have anti-A or anti-B antibodies in their plasma.
Q4. Which blood component is primarily responsible for transporting oxygen from the lungs to the rest of the body?
a) White blood cells
b) Red blood cells
c) Plasma
d) Platelets
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Correct Answer: b) Red blood cells
Explanation: Red blood cells are primarily responsible for transporting oxygen from the lungs to the body’s tissues and organs. They contain hemoglobin, a protein that binds oxygen in the lungs and releases it in the tissues.
Q5. The lifespan of a typical human red blood cell is approximately:
a) 30 days
b) 60 days
c) 120 days
d) 180 days
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Correct Answer: c) 120 days
Explanation: The average lifespan of a human red blood cell is about 120 days. After this time, they are typically removed from circulation by the spleen and liver, where they are broken down, and their components are recycled.
Q6. Blood clotting or coagulation involves the conversion of fibrinogen into:
a) Albumin
b) Globulin
c) Fibrin
d) Hemoglobin
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Correct Answer: c) Fibrin
Explanation: Blood clotting involves the conversion of the soluble plasma protein fibrinogen into insoluble fibrin. Fibrin strands form a mesh that traps blood cells, leading to the formation of a stable blood clot, which is essential for stopping bleeding.
Q7. White blood cells that are important in producing antibodies are called:
a) Neutrophils
b) Eosinophils
c) Lymphocytes
d) Monocytes
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Correct Answer: c) Lymphocytes
Explanation: Lymphocytes, a type of white blood cell, are crucial in the immune system’s response to infectious disease and foreign materials. They are subdivided into B cells and T cells, with B cells particularly important for producing antibodies.
Q8. The protein in red blood cells that carries oxygen is called:
a) Albumin
b) Globulin
c) Hemoglobin
d) Fibrinogen
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Correct Answer: c) Hemoglobin
Explanation: Hemoglobin is the iron-containing protein in red blood cells that is responsible for transporting oxygen from the lungs to the body’s tissues. It binds oxygen molecules, giving red blood cells their characteristic red color.
Q9. Which of the following is a primary function of blood plasma?
a) Transporting oxygen
b) Clotting blood
c) Transporting nutrients and waste
d) Fighting infections
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Correct Answer: c) Transporting nutrients and waste
Explanation: Blood plasma plays a key role in transporting nutrients, waste products, hormones, and other substances throughout the body. Comprising about 55% of blood’s total volume, it is a medium for cells and other components to travel in.
Q10. A decrease in platelet count can lead to a condition known as:
a) Anemia
b) Thrombocytopenia
c) Leukopenia
d) Polycythemia
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Correct Answer: b) Thrombocytopenia
Explanation: Thrombocytopenia is a condition characterized by a low platelet count in the blood, leading to a reduced ability to form blood clots. This can result in excessive bleeding and bruising, even from minor injuries.