The vitamin which is effective in blood clotting is
- A.Vitamin A
- B.Vitamin K
- C.Vitamin D
- D.Vitamin B
Correct answer
Explanation
The correct answer is B, Vitamin K. The liver needs vitamin K to make prothrombin and other clotting factors, so without it blood takes much longer to clot. The letter K comes from the German word Koagulation, which makes it easy to remember. Vitamin K1, or phylloquinone, comes from green leafy vegetables such as spinach, and bacteria in the large intestine also make a form of it. Newborn babies have very little vitamin K, which is why they are given a vitamin K injection at birth to prevent bleeding. A lack of it causes easy bruising and bleeding that does not stop. Option A is wrong because vitamin A, retinol, is needed for vision, and its lack causes night blindness. Option C is wrong because vitamin D, calciferol, helps absorb calcium, and its lack causes rickets. Option D is wrong because the B vitamins help release energy from food, and their lack causes diseases such as beriberi and pernicious anaemia. Exam tip: K for Koagulation; A for eyes, D for bones.
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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