This set of Biology Multiple Choice Questions & Answers (MCQs) focuses on “Body Fluids and Circulation Basics”.
1. Which of the following is the most commonly used body fluid?
Explanation: Blood is the most commonly used body fluid by most of the higher organisms including humans for the transportation of essential nutrients to the body tissues. Another body fluid, lymph also helps in the transport of certain substances.
2. Which of the following is absent on blood?
a) Fluid matrix
d) Formed elements
Explanation: Fibroblast are special cells which are responsible for the formation of fibres in the areolar tissue which is a type of connective tissue. Blood is a special type of connective tissue which consists of a fluid matrix, plasma and formed elements.
3. How much percentage of plasma is present in the blood?
Explanation: Plasma constitutes nearly 55% of the blood. 90-92% of plasma is water and proteins contribute 6-8 per cent of it. Fibrinogens, albumins and globulins are the major proteins.
4. Which of the following are needed for clotting of blood?
d) Magnesium ions
Explanation: Fibrinogens are needed for clotting or coagulation of blood. Globulins primarily are involved in defence mechanisms of the body and the albumins help in the osmotic balance.
5. What is plasma without clotting factors known as?
Explanation: Plasma without the clotting factors is known as serum. Factors for coagulation or clotting of blood are also present in the plasma in an inactive form.
6. Which of the following is not a formed element?
Explanation: Erythrocytes, leucocytes and platelets are collectively called as formed elements. They constitute nearly 45% of the blood. A reduction in these number can lead to numerous disorders.
7. RBCs are formed in the thymus.
Explanation: RBCs are formed in the red bone marrow in the adults. RBCs are devoid of the nucleus in most of the mammals and are biconcave in shape. They have a red coloured iron-containing pigment called haemoglobin.
8. What is the average life span of RBCs?
a) 120 seconds
b) 120 hours
c) 120 days
d) 120 weeks
Explanation: RBCs have an average life span of about 120 days after which they are destroyed in the spleen which is also known as the graveyard of RBCs. These molecules play a significant role in the transport of gases.
9. What is the colour of leucocytes?
Explanation: Leucocytes which are also known as white blood cells because they are colourless in nature as they lack haemoglobin. They are nucleated and are relatively lesser in number as compared to RBCs.
10. WBCs are characterised into 4 main categories.
Explanation: WBCs are characterised into 2 main categories- granulocytes and agranulocytes. Neutrophils, eosinophils and basophils are different types of granulocytes while lymphocytes and monocytes are the agranulocytes.
11. Which of the following are the most abundant in WBCs?
Explanation: Neutrophils are the most abundant cells of the total WBCs as they constitute about 60-65 per cent of the total. Basophils are the least amongst as they constitute only 0.5-1 per cent of the total WBCs.
12. Which of the following is not secreted by basophils?
Explanation: Basophils secrete histamine, serotonin and heparin which are involved in the inflammatory reactions. Histamine acts as a vasodilator while serotonin acts as a vasoconstrictor.
13. Which of the following WBCs are involved in allergic reactions?
Explanation: Eosinophils resist infections and are also associated with allergic reactions. Neutrophils and monocytes are phagocytic cells which destroy foreign organisms entering the body.
14. Lymphocytes constitute how much per cent of the total WBCs?
Explanation: Lymphocytes constitute for about 20-25% of the total WBCs. These are of two major types-B and T forms. Both B and T lymphocytes are responsible for the immune responses of the body.
15. Platelets are produced from which of the following cells?
Explanation: Platelets are also called thrombocytes which are the cell fragments produced from megakaryocytes which are the special cells in the bone marrow.
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