In nucleic acids, the heterocyclic bases are connected to `D`-ribofuranose by a covalent bond between the `N` atom of the heterocyclic ring and the - of the sugar through a `beta`-linkage, i.e., by replacing the `beta-OH` group of the latter.

Monosaccharides are polyhydric aldehydes and ketones which cannot be hydrolysed into simpler carbohydrates. The monosaccharides containing -CHO group are called aldoses while those containing C=O group are called ketoses. The aldehyde group is always present at C_(1) while keto group is generally present at C_(2) . All monosaccharides are oxidised by Tollen's reagent and Fehling solution and are called reducing sugars. The monosaccharide molecules may be assigned D and L-configurations depending upon whether the configuration of the molecule is related to D- or L-glyceraldehyde. If the -OH group is attached to the carbon adjacent to the -CH_(2)OH group (last chiral carbon) is on the right hand side, it is assigned D-configuration. The molecule is assigned L-configuration if the -OH group attached to the carbon adjacent to the -CH_(2)OH group is on the left. The monosaccharides contain one or more chiral carbon atoms. Pentoses and hexoses have cyclic structures furanose (five membered) and pyranose (six membered). During cyclization, C_(1) in aldohexoses and C_(2) in fructose become chiral and the newly formed -OH group may be either on the left or on the right in Fischer projection formulae. These monosaccharides, therefore, exist in two stereoisomeric forms called alpha -anomer and beta -anomer while C_(1) and C_(2) are called glycosidic or anomeric carbon. The bonds joining glycosidic carbon are called glycosidic linkages. D(+) glucose exists in two stereoisomeric forms, alpha -D- glucose and beta -D-glucose. When either of these two forms of glucose i.e., alpha-D- glucose are dissolved in water and allowed to stand, these get slowly converted into other form and an equilibrium mixture of both is formed. This process is called mutarotation. Two forms of D-glucopyranose are called

Monosaccharides are polyhydric aldehydes and ketones which cannot be hydrolysed into simpler carbohydrates. The monosaccharides containing -CHO group are called aldoses while those containing C=O group are called ketoses. The aldehyde group is always present at C_(1) while keto group is generally present at C_(2) . All monosaccharides are oxidised by Tollen's reagent and Fehling solution and are called reducing sugars. The monosaccharide molecules may be assigned D and L-configurations depending upon whether the configuration of the molecule is related to D- or L-glyceraldehyde. If the -OH group is attached to the carbon adjacent to the -CH_(2)OH group (last chiral carbon) is on the right hand side, it is assigned D-configuration. The molecule is assigned L-configuration if the -OH group attached to the carbon adjacent to the -CH_(2)OH group is on the left. The monosaccharides contain one or more chiral carbon atoms. Pentoses and hexoses have cyclic structures furanose (five membered) and pyranose (six membered). During cyclization, C_(1) in aldohexoses and C_(2) in fructose become chiral and the newly formed -OH group may be either on the left or on the right in Fischer projection formulae. These monosaccharides, therefore, exist in two stereoisomeric forms called alpha -anomer and beta -anomer while C_(1) and C_(2) are called glycosidic or anomeric carbon. The bonds joining glycosidic carbon are called glycosidic linkages. D(+) glucose exists in two stereoisomeric forms, alpha -D- glucose and beta -D-glucose. When either of these two forms of glucose i.e., alpha-D- glucose are dissolved in water and allowed to stand, these get slowly converted into other form and an equilibrium mixture of both is formed. This process is called mutarotation. The maximum number of optical isomers of glucose expected are

Monosaccharides are polyhydric aldehydes and ketones which cannot be hydrolysed into simpler carbohydrates. The monosaccharides containing -CHO group are called aldoses while those containing C=O group are called ketoses. The aldehyde group is always present at C_(1) while keto group is generally present at C_(2) . All monosaccharides are oxidised by Tollen's reagent and Fehling solution and are called reducing sugars. The monosaccharide molecules may be assigned D and L-configurations depending upon whether the configuration of the molecule is related to D- or L-glyceraldehyde. If the -OH group is attached to the carbon adjacent to the -CH_(2)OH group (last chiral carbon) is on the right hand side, it is assigned D-configuration. The molecule is assigned L-configuration if the -OH group attached to the carbon adjacent to the -CH_(2)OH group is on the left. The monosaccharides contain one or more chiral carbon atoms. Pentoses and hexoses have cyclic structures furanose (five membered) and pyranose (six membered). During cyclization, C_(1) in aldohexoses and C_(2) in fructose become chiral and the newly formed -OH group may be either on the left or on the right in Fischer projection formulae. These monosaccharides, therefore, exist in two stereoisomeric forms called alpha -anomer and beta -anomer while C_(1) and C_(2) are called glycosidic or anomeric carbon. The bonds joining glycosidic carbon are called glycosidic linkages. D(+) glucose exists in two stereoisomeric forms, alpha -D- glucose and beta -D-glucose. When either of these two forms of glucose i.e., alpha-D- glucose are dissolved in water and allowed to stand, these get slowly converted into other form and an equilibrium mixture of both is formed. This process is called mutarotation. Which of the following statements is not correct?

Monosaccharides are polyhydric aldehydes and ketones which cannot be hydrolysed into simpler carbohydrates. The monosaccharides containing -CHO group are called aldoses while those containing C=O group are called ketoses. The aldehyde group is always present at C_(1) while keto group is generally present at C_(2) . All monosaccharides are oxidised by Tollen's reagent and Fehling solution and are called reducing sugars. The monosaccharide molecules may be assigned D and L-configurations depending upon whether the configuration of the molecule is related to D- or L-glyceraldehyde. If the -OH group is attached to the carbon adjacent to the -CH_(2)OH group (last chiral carbon) is on the right hand side, it is assigned D-configuration. The molecule is assigned L-configuration if the -OH group attached to the carbon adjacent to the -CH_(2)OH group is on the left. The monosaccharides contain one or more chiral carbon atoms. Pentoses and hexoses have cyclic structures furanose (five membered) and pyranose (six membered). During cyclization, C_(1) in aldohexoses and C_(2) in fructose become chiral and the newly formed -OH group may be either on the left or on the right in Fischer projection formulae. These monosaccharides, therefore, exist in two stereoisomeric forms called alpha -anomer and beta -anomer while C_(1) and C_(2) are called glycosidic or anomeric carbon. The bonds joining glycosidic carbon are called glycosidic linkages. D(+) glucose exists in two stereoisomeric forms, alpha -D- glucose and beta -D-glucose. When either of these two forms of glucose i.e., alpha-D- glucose are dissolved in water and allowed to stand, these get slowly converted into other form and an equilibrium mixture of both is formed. This process is called mutarotation. Mutarotation does not occur in

Monosaccharides are polyhydric aldehydes and ketones which cannot be hydrolysed into simpler carbohydrates. The monosaccharides containing -CHO group are called aldoses while those containing C=O group are called ketoses. The aldehyde group is always present at C_(1) while keto group is generally present at C_(2) . All monosaccharides are oxidised by Tollen's reagent and Fehling solution and are called reducing sugars. The monosaccharide molecules may be assigned D and L-configurations depending upon whether the configuration of the molecule is related to D- or L-glyceraldehyde. If the -OH group is attached to the carbon adjacent to the -CH_(2)OH group (last chiral carbon) is on the right hand side, it is assigned D-configuration. The molecule is assigned L-configuration if the -OH group attached to the carbon adjacent to the -CH_(2)OH group is on the left. The monosaccharides contain one or more chiral carbon atoms. Pentoses and hexoses have cyclic structures furanose (five membered) and pyranose (six membered). During cyclization, C_(1) in aldohexoses and C_(2) in fructose become chiral and the newly formed -OH group may be either on the left or on the right in Fischer projection formulae. These monosaccharides, therefore, exist in two stereoisomeric forms called alpha -anomer and beta -anomer while C_(1) and C_(2) are called glycosidic or anomeric carbon. The bonds joining glycosidic carbon are called glycosidic linkages. D(+) glucose exists in two stereoisomeric forms, alpha -D- glucose and beta -D-glucose. When either of these two forms of glucose i.e., alpha-D- glucose are dissolved in water and allowed to stand, these get slowly converted into other form and an equilibrium mixture of both is formed. This process is called mutarotation. Which of the following pairs give positive Tollen's test?

The two monosaccharides are joined together by an oxide linkage formed by the loss of a water molecule. Such a linkage between two monosaccharide units through oxygen atom is called glycosidic linkage. In disaccharides, if the reducing groups of monosaccharides i.e., aldehydic or ketonic groups are bonded, these are non-reducing sugars, e.g., sucrose. On the other hand, sugars in which these functional groups are free, are called reducing sugars, for example, maltose and lactose. A non reducing disaccharide 'A on hydrolysis with dilute acid gives an equimolar mixture of D-(+)glucose and D-(+)-Fructose. Name the linkage that holds the two units in the disaccharide?

The two monosaccharides are joined together by an oxide linkage formed by the loss of a water molecule. Such a linkage between two monosaccharide units through oxygen atom is called glycosidic linkage. In disaccharides, if the reducing groups of monosaccharides i.e., aldehydic or ketonic groups are bonded, these are non-reducing sugars, e.g., sucrose. On the other hand, sugars in which these functional groups are free, are called reducing sugars, for example, maltose and lactose. A non reducing disaccharide 'A on hydrolysis with dilute acid gives an equimolar mixture of D-(+)glucose and D-(+)-Fructose. Glucose on reaction with acetic acid gives glucose pentaacetate. What does it suggest about the structure of glucose ?

The two monosaccharides are joined together by an oxide linkage formed by the loss of a water molecule. Such a linkage between two monosaccharide units through oxygen atom is called glycosidic linkage. In disaccharides, if the reducing groups of monosaccharides i.e., aldehydic or ketonic groups are bonded, these are non-reducing sugars, e.g., sucrose. On the other hand, sugars in which these functional groups are free, are called reducing sugars, for example, maltose and lactose. A non reducing disaccharide 'A on hydrolysis with dilute acid gives an equimolar mixture of D-(+)glucose and D-(+)-Fructose. What is the mixture of D-(+) glucose and D-(+) fructose known as ?

The two monosaccharides are joined together by an oxide linkage formed by the loss of a water molecule. Such a linkage between two monosaccharide units through oxygen atom is called glycosidic linkage. In disaccharides, if the reducing groups of monosaccharides i.e., aldehydic or ketonic groups are bonded, these are non-reducing sugars, e.g., sucrose. On the other hand, sugars in which these functional groups are free, are called reducing sugars, for example, maltose and lactose. A non reducing disaccharide 'A on hydrolysis with dilute acid gives an equimolar mixture of D-(+)glucose and D-(+)-Fructose. In the above reaction, reactant 'A' is:

Mesomerism is extended resonance. Atoms or groups with lone pairs of electrons release electrons when connected to doubly bonded carbons. It is +M effect. Unsaturated groups when connected to doubly bonded carbons withdraw pi electrons from the doubly bonded carbons. It is -M effect. Here the double bond is the unsaturated group should be between less electronegative atom and more electronegative atom. Mesomeric effect stabilizes or destabilizes the conjugate base of an acid. As a result the acid may be strong or weak has 4(OH) groups. Which -OH is a strong acid?