C6H12O6 (aq) + 6O2 (aq) → 6CO2 (aq) + 6H2O (l) + energy. The special name for the given reaction is:
- A.metabolism
- B.digestion
- C.respiration
- D.energy conversion
Correct answer
Explanation
The correct answer is C, respiration. In the equation given, glucose reacts with oxygen to release carbon dioxide, water and energy, and the breakdown of food inside the cell to release energy is called respiration. Oxygen is used here, so this is aerobic respiration, and it takes place in the mitochondria, which is why the mitochondrion is called the powerhouse of the cell. The energy released is stored in ATP. Without oxygen, muscle cells break glucose down only to lactic acid and yeast breaks it down to ethanol and carbon dioxide, and both of these release far less energy. A is wrong because metabolism is the whole set of chemical reactions going on in the body, of which respiration is only one. B is wrong because digestion merely breaks large food molecules into simpler ones such as glucose and does not release energy in this way. D is wrong because energy conversion is a loose general phrase, not the name of this reaction. Exam tip: glucose plus oxygen giving carbon dioxide, water and energy is aerobic respiration; without oxygen it gives lactic acid in muscles and ethanol in yeast.
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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