Which of the following is NOT the correct match?
- A.The acid present in tomato - Formic acid
- B.The acid present in orange - Citric acid
- C.The acid present in grapes - Tartaric acid
- D.The acid present in rancid butter - Butyric acid
Correct answer
Explanation
The correct answer is A, The acid present in tomato - Formic acid. This pair is wrong, because tomato contains oxalic acid, along with some citric and malic acid.
Formic acid, or methanoic acid, is the acid of an ant sting and a bee sting, and its name comes from the Latin word for ant. Oxalic acid is found in tomato, spinach and other leafy vegetables. Learning the natural acids as pairs is the quickest way to handle such questions: lemon and orange give citric acid, curd gives lactic acid, vinegar gives acetic acid, apple gives malic acid and tamarind gives tartaric acid.
B is a correct match, so it is not the answer: orange does contain citric acid. C is correct as well, because grapes and tamarind contain tartaric acid. D is also correct, since rancid butter smells the way it does because of butyric acid.
Exam tip: Tomato - oxalic acid; ant sting - formic acid; do not mix the two.
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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