Biomolecules

The correct statement(s) regarding sugars is(are) Given: Specific rotations of L-(−)-glucose and L-(+)-fructose are -52.5 and +92.5 , respectively.

1. On treatment with HNO3, gluconic acid is oxidized to saccharic acid, whereas glucose is not oxidized to saccharic acid.
2. Fructose gives a positive Fehling's test because it isomerises to glucose and another aldohexose in the presence of Fehling's reagent.
3. Invert sugar is an equimolar mixture of D-glucose and D-fructose formed after hydrolysis of the corresponding disaccharide.
4. Specific rotation of invert sugar is -40 .

A known artificial sweetener X is composed of 4-chloro-4-deoxy-α-D-galactose and 1,6-dichloro-1,6-dideoxy-β-D-fructose joined by a glycosidic linkage. Structure of D-galactose is given below: [figure] The correct structure of X is

1. [figure]
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A linear octasaccharide (molar mass = 1024 g mol-1) on complete hydrolysis produces three monosaccharides: ribose, 2-deoxyribose and glucose. The amount of 2-deoxyribose formed is 58.26 % (w/w) of the total amount of the monosaccharides produced in the hydrolyzed products. The number of ribose unit(s) present in one molecule of octasaccharide is . Use: Molar mass (in g mol-1): ribose = 150, 2-deoxyribose = 134, glucose = 180; Atomic mass (in amu): H = 1, O = 16

Aspartame, an artificial sweetener, is a dipeptide aspartyl phenylalanine methyl ester. The structure of aspartame is [figure]

1. [figure]
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For a double strand DNA, one strand is given below: [figure] The amount of energy required to split the double strand DNA into two single strands is kcal mol-1. [Given: Average energy per H-bond for A-T base pair = 1.0 kcal mol-1, G-C base pair = 1.5 kcal mol-1, and A-U base pair = 1.25 kcal mol-1. Ignore electrostatic repulsion between the phosphate groups.]