Biomolecules MCQ Questions & Answers in Organic Chemistry | Chemistry

Since the compound forms a yellow crystalline solid, i.e. osazone with phenylhydrazine, it may be an aldohexose or a ketohexose. Further, since on reduction, compound forms a mixture of sorbitol and mannitol, it must be a ketohexose, i.e. fructose. Recall that glucose on reduction gives only one alcohol glucitol (Sorbitol)

$$6C{O_2} + 12NADPH + 18ATP \to {C_6}{H_{12}}{O_6} + 12NADP + 18ADP$$

Thymine is not present in $$RNA.$$  $$RNA$$  contains uracil in place of thymine.

The number of chiral carbon atoms in $$\beta - D - \left( + \right)$$    glucose are five

Glycogen is the reserve carbohydrate occurring mainly in the liver.

Glycosidic linkage is actually an ether bond as the linkage forming the rings in an oligosaccharide or polysaccharide is not just one bond, but the two bonds sharing an oxygen atom e.g. sucrose

Vitamin $$E$$  is mainly present in vegetable oils like wheat germ oil, sunflower oil, etc.

The segment of $$DNA$$  which acts as the instrumental manual for the synthesis of the protein is gene. Every protein in a cell has a corresponding gene.

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The aqueous solution of sucrose is dextrorotatory having $${\left[ \alpha \right]_D} = + {66.4^ \circ }.$$    On hydrolysis with dilute acids or enzyme invertase, cane sugar (sucrose) gives equimolar mixture of $$D{\text{ - }}\left( + \right){\text{ - }}$$  glucose and $$D{\text{ - }}\left( - \right){\text{ - }}$$  fructose
\[\underset{\begin{smallmatrix} \text{Cane sugar} \\ {{\left[ \alpha \right]}_{D}}={{66.4}^{\circ }} \end{smallmatrix}}{\mathop{{{C}_{12}}{{H}_{22}}{{O}_{11}}}}\,+{{H}_{2}}O\xrightarrow{HCl}\underset{\begin{smallmatrix} \text{D}\,\text{-}\,\text{glucose} \\ {{\left[ \alpha \right]}_{D}}=\,+52.5 \end{smallmatrix}}{\mathop{{{C}_{6}}{{H}_{12}}{{O}_{6}}}}\,+\underset{\begin{smallmatrix} \text{D}\,\text{-fructose} \\ {{\left[ \alpha \right]}_{D}}=\,-{{92.4}^{\circ }} \end{smallmatrix}}{\mathop{{{C}_{6}}{{H}_{12}}{{O}_{6}}}}\,\]
So, sucrose is dextrorotatory but after hydrolysis gives dextrorotatory glucose and laevorotatory fructose. $$D{\text{ - }}\left( - \right){\text{ - }}$$  fructose has a greater specific rotation than $$D{\text{ - }}\left( + \right){\text{ - }}$$  glucose. Therefore, the resultant solution is laevorotatory in nature with specific rotation of \[-{{39.9}^{\circ }}.\]