Which one of the following blood cells type secrete large number of antibodies during an immune response of the body ?
- A.Neutrophils
- B.Eosinophils
- C.Lymphocytes
- D.Monocytes
Correct answer
Explanation
The correct answer is C, Lymphocytes. Antibodies are made by B lymphocytes, which turn into plasma cells that release antibodies in very large numbers during an immune response.
Lymphocytes are white blood cells of two main kinds. B lymphocytes recognise a particular antigen, multiply, and change into plasma cells, each of which can pour out thousands of antibody molecules every second; some remain as memory cells, which is why a second infection or a vaccine booster gets a faster response. T lymphocytes do not make antibodies; they kill infected cells and help control the response. Lymphocytes form roughly 20 to 40 per cent of white blood cells.
A is wrong because neutrophils, the most numerous white cells, engulf and destroy bacteria by phagocytosis. B is wrong because eosinophils act against parasites and in allergic reactions. D is wrong because monocytes become macrophages that swallow microbes and debris.
Exam tip: Antibodies come from B lymphocytes (plasma cells); neutrophils and monocytes are the phagocytes.
Practice Questions
View allThe fact that the planets move around the Sun, not in circles but in ellipses, was first demonstrated by
- A.Galileo
- B.Martin Luther
- C.Johannes Kepler
- D.Copernicus
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In 1609 Kepler showed that the planets move around the Sun in elliptical orbits, with the Sun at one focus of the ellipse.
Read the full explanation →Which one of the following statements is correct?
- A.Urea is produced in liver.
- B.Urea is produced in blood.
- C.Urea is produced from digestion of starch.
- D.Urea is produced in lung and kidney.
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Liver cells turn the toxic ammonia released from the breakdown of amino acids into urea through the ornithine cycle, also called the urea cycle.
Read the full explanation →Which one of the following is the correct sequence of passage of light in a compound microscope?
- A.Condenser-Objective lens-Eyepiece-Body tube
- B.Objective lens-Condenser-Body tube-Eyepiece
- C.Condenser-Objective lens-Body tube-Eyepiece
- D.Eyepiece-Objective lens-Body tube-Mirror
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Light passes through the condenser to the specimen, is picked up by the objective lens, travels up the body tube and reaches the eye through the eyepiece.
Read the full explanation →Which one of the following statements regarding haemoglobin is correct?
- A.Haemoglobin present in RBC can carry only oxygen but not carbon dioxide.
- B.Haemoglobin of RBC can carry both oxygen and carbon dioxide.
- C.Haemoglobin of RBC can carry only carbon dioxide.
- D.Haemoglobin is only used for blood clotting and not for carrying gases.
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It binds oxygen at its iron-containing haem groups and carries some carbon dioxide on its protein chains. Each haemoglobin molecule has four polypeptide chains and four haem groups, and each haem iron can hold one oxygen molecule, forming oxyhaemoglobin in the lungs.
Read the full explanation →Which one of the following statements regarding histone proteins is correct?
- A.Histones are proteins that are present in mitochondrial membrane.
- B.Histones are proteins that are present in nucleus in association with DNA.
- C.Histones are proteins associated with lipids in the cytosol.
- D.Histones are proteins associated with carbohydrates in the cytosol.
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They are the proteins around which DNA winds to form chromatin in the nucleus of eukaryotic cells. Histones are small basic proteins, rich in the positively charged amino acids lysine and arginine, which attract the negatively charged phosphate groups of DNA.
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