Unit 14 Biomolecules (Intext Questions-3)
Intext Questions
14.6 Why cannot vitamin C be stored in our body?
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Answer
Vitamin $\mathrm{C}$ cannot be stored in our body because it is water soluble. As a result, it is readily excreted in the urine.
14.7 What products would be formed when a nucleotide from DNA containing thymine is hydrolysed?
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Answer
When a nucleotide from the DNA containing thymine is hydrolyzed, thymine $\beta$-D-2-deoxyribose and phosphoric acid are obtained as products.
14.8 When RNA is hydrolysed, there is no relationship among the quantities of different bases obtained. What does this fact suggest about the structure of RNA?
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Answer
A DNA molecule is double-stranded in which the pairing of bases occurs. Adenine always pairs with thymine, while cytosine always pairs with guanine. Therefore, on hydrolysis of DNA, the quantity of adenine produced is equal to that of thymine and similarly, the quantity of cytosine is equal to that of guanine.
But when RNA is hydrolyzed, there is no relationship among the quantities of the different bases obtained. Hence, RNA is single-stranded.
