Question

Study carefully the following statements and select the incorrect ones.
(i) When fats are used in respiration, the RQ is more than unity because fats contain more $O_2$ and require relatively less amount of $O_2$ for oxidation.
(ii) The most important energy carrier is ATP. This energy-rich compound is mobile and can pass from one cell to another.
(iii) Before pyruvic acid enters Krebs' cycle, one of the two carbon atoms of pyruvic acid is reduced to carbon atoms of pyruvic acid is reduced to carbon dioxide in the reaction called reductive carboxylation.
(iv) A special electron carrier system located in the mitochondrial membrane is called a shuttle system. It transfers electrons from the hydrogens of cytoplasmic NADH to the mitochondrial electron carriers across the mitochondrial membrane.
(v) Zymase is a complex mixture of many enzymes which requires several coenzymes for its action. The enzyme complex-zymase catalyses series of reactions taking place during fermentation leading to the production of ethyl alcohol.

• A. (i) and (ii)
• B. (iii) and (iv)
• C. (i),(ii) and (iii)
• D. (iii),(iv) and (v)

Answer 1

Answer: (C)

(i),(ii) and (iii)

When fats are used as respiratory substrates, RQ is usually less than one. Fats are hydrolysed during respiration to glycerol and fatty acids. Complete oxidation of glycerol results in the RQ of 0.86. The fatty acids, being poorer in oxygen, require more $O_2$ for complete oxidation. ATP (Adenosine triphosphate) is the most important energy carrier. ATP is mobile and transports the chemical energy to the energy consuming processes anywhere within the cell, however, the ATP molecules do not pass from one cell to another. Pyruvic acid, generated in the glycolysis, enters into mitochondrial matrix and one of the three C atoms of pyruvic acid undergoes oxidative decarboxylation before it enters Krebs' cycle.

So the correct answer is '(i),(ii) and (iii)'.